GO:1904199 positive regulation of regulation of vascular associated smooth muscle cell membrane depolarization: Vascular Excitability Control, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:1904199 describes any process that activates or increases the frequency, rate or extent of regulation of vascular associated smooth muscle cell membrane depolarization, placing it at the top of a regulatory hierarchy that tunes vascular smooth muscle excitability.
• Membrane depolarization of vascular smooth muscle cells is a graded, tension- and agonist-sensitive process that can be recorded electrophysiologically in intact arteries.
• Depolarization is functionally coupled to vasoconstriction and is limited by negative-feedback mechanisms such as BK channel trafficking to the surface membrane.
• Ion overload and oxidative stress during phosphate-induced vascular calcification are linked to altered Ca2+ handling and membrane behavior in vascular smooth muscle cells.
• Serotonergic and mechanical stimuli can shift the electrical and mechanical activity of vascular smooth muscle, showing that the regulation of depolarization is multimodal.
• Because the term sits at a second regulatory layer, researchers must distinguish direct modulators of depolarization from upstream regulators of those modulators when designing CRISPR models.
Description
GO:1904199, positive regulation of regulation of vascular associated smooth muscle cell membrane depolarization, is a biological_process term in the Gene Ontology that captures an additional layer of control over vascular smooth muscle excitability. Rather than describing depolarization itself, the term describes processes that activate or increase the frequency, rate or extent of the regulation of vascular associated smooth muscle cell membrane depolarization. This hierarchical placement matters because vascular smooth muscle membrane potential is not a fixed property; it is continuously adjusted by mechanical tension, vasoactive agonists and ion channel trafficking. Electrophysiological studies of rat middle cerebral artery show that passive wall tension changes the electrical properties of the smooth muscle membrane, demonstrating that depolarization is itself a regulated variable. In rabbit jugular vein grafts, 5-hydroxytryptamine modifies both electrical and mechanical activity, indicating that agonist-driven regulation of depolarization is physiologically meaningful. At the same time, depolarization activates BK channels through ROCK-mediated beta1 subunit surface trafficking to limit vasoconstriction, a negative-feedback mechanism that constrains how far depolarization can proceed. Together these findings show that the regulation of vascular smooth muscle depolarization is a real, measurable and therapeutically relevant process, and that positive regulation of that regulation is a distinct node for experimental interrogation. For researchers, GO:1904199 provides a formal way to annotate genes and pathways that amplify the control of vascular smooth muscle membrane potential, which is relevant to vascular tone, calcification and cardiovascular disease modeling.
positive regulation of regulation of vascular associated smooth muscle cell membrane depolarization At A Glance
| GO ID | GO:1904199 |
|---|---|
| GO term | positive regulation of regulation of vascular associated smooth muscle cell membrane depolarization |
| Ontology | biological_process |
| Synonym | activation of regulation of vascular smooth muscle cell membrane depolarization; positive regulation of regulation of vascular smooth muscle cell membrane depolarization; up regulation of regulation of vascular smooth muscle cell membrane depolarization; up-regulation of regulation of vascular smooth muscle cell membrane depolarization; upregulation of regulation of vascular smooth muscle cell membrane depolarization |
| Major function | Increases the frequency, rate or extent of the regulation of vascular associated smooth muscle cell membrane depolarization |
| Cell type | Vascular associated smooth muscle cells |
| Process level | Second-order regulation of a membrane potential regulatory process |
| Related physiology | Vascular tone, vasoconstriction and electromechanical coupling |
| Experimental readouts | Membrane potential recordings, tension measurements, ion channel trafficking assays |
What Is GO:1904199?
In plain terms, GO:1904199 is the GO term for any process that turns up or strengthens the regulation of membrane depolarization in vascular associated smooth muscle cells. The QuickGO definition states that it is any process that activates or increases the frequency, rate or extent of regulation of vascular smooth muscle cell membrane depolarization. It is a biological_process term, and its synonyms include activation of regulation of vascular smooth muscle cell membrane depolarization, positive regulation of regulation of vascular smooth muscle cell membrane depolarization, up regulation of regulation of vascular smooth muscle cell membrane depolarization, up-regulation of regulation of vascular smooth muscle cell membrane depolarization and upregulation of regulation of vascular smooth muscle cell membrane depolarization. The double 'regulation of regulation' wording is intentional: the term does not directly describe the depolarization event, but the positive control of the machinery that regulates that event. This makes it a higher-order regulatory annotation, useful when a gene or pathway increases the gain or sensitivity of depolarization control rather than simply causing depolarization.
Why Is positive regulation of regulation of vascular associated smooth muscle cell membrane depolarization Important in Cell Biology?
GO:1904199 is important because vascular smooth muscle membrane potential is a central determinant of arterial tone, and the regulation of that potential is itself subject to positive control. Electrophysiological work on rat middle cerebral artery demonstrates that passive wall tension alters the electrical properties of the smooth muscle membrane, meaning that the set point for depolarization is dynamically regulated. In rabbit jugular vein grafts, 5-hydroxytryptamine changes both electrical and mechanical activity, showing that agonist-dependent modulation of depolarization has direct mechanical consequences. Depolarization also engages feedback braking through BK channels, where ROCK-mediated beta1 subunit surface trafficking limits vasoconstriction. In disease contexts, oxidative stress caused by Ca2+ overload is critical for phosphate-induced vascular calcification, linking disturbed Ca2+ handling and membrane behavior to vascular pathology. Therefore, annotating genes under GO:1904199 helps researchers identify nodes that amplify or tune the regulation of depolarization, which may be relevant to hypertension, vasospasm, vascular calcification and other cardiovascular conditions.
• Provides a formal ontology handle for genes that increase the gain of vascular smooth muscle depolarization control.
• Connects membrane potential regulation to vasoconstriction and vascular tone through electromechanical coupling.
• Highlights feedback mechanisms such as BK channel trafficking that limit depolarization and vasoconstriction.
• Supports mechanistic studies of agonist-driven electrical changes in vascular smooth muscle, including serotonergic modulation.
• Links the regulation of depolarization to Ca2+ overload and oxidative stress in vascular calcification.
• Helps distinguish direct depolarization effectors from upstream regulators of those effectors in experimental design.
• Offers a framework for electrophysiological phenotyping of arteries at different passive wall tensions.
• Guides CRISPR knockout, knock-in and overexpression strategies for genes that modulate vascular excitability.
• Supports translational research into hypertension, vasospasm and vascular remodeling.
• Enables bioinformatic enrichment of vascular smooth muscle gene sets at a higher regulatory level.
What Happens During positive regulation of regulation of vascular associated smooth muscle cell membrane depolarization?
Setting the resting electrical state of vascular smooth muscle
In simple terms: First, the smooth muscle cell establishes a baseline membrane potential that can later be regulated.
Vascular associated smooth muscle cells maintain a resting membrane potential that depends on the balance of ion conductances and on the mechanical state of the vessel wall. Electrophysiological recordings from rat middle cerebral artery at different levels of passive wall tension show that the electrical properties of the smooth muscle membrane change with tension, establishing that the baseline electrical state is not fixed. This baseline is the substrate on which any regulation of depolarization operates, and positive regulation of that regulation would increase the sensitivity or strength of the mechanisms that adjust this baseline.
Agonist-driven modulation of depolarization
In simple terms: Second, circulating or locally released signals can shift the membrane potential up or down.
Vasoactive agonists can modify the electrical activity of vascular smooth muscle. In rabbit jugular vein grafts, 5-hydroxytryptamine affects both electrical and mechanical activities, demonstrating that agonist stimulation can change the depolarization state and thereby contraction. Positive regulation of the regulation of depolarization would correspond to processes that enhance the ability of such agonists, or of the downstream signaling they engage, to adjust membrane potential.
Feedback limitation through BK channel trafficking
In simple terms: Third, when the cell depolarizes, a braking mechanism moves BK channels to the surface to limit further constriction.
Depolarization activates BK channels through ROCK-mediated beta1 subunit surface trafficking to limit vasoconstriction. This is a negative-feedback loop that constrains depolarization, and it illustrates that the regulation of depolarization is itself a target of regulation. Positive regulation of the regulation of depolarization could act by strengthening such feedback or by modulating the trafficking step, thereby changing the effective gain of the depolarization-control system.
Coupling of membrane potential to contraction
In simple terms: Fourth, changes in membrane potential are translated into mechanical output.
The electrical and mechanical activities of vascular smooth muscle are coupled, as shown by simultaneous recordings in rabbit jugular vein grafts where 5-hydroxytryptamine altered both parameters. Because contraction depends on depolarization-driven Ca2+ entry, any process that positively regulates the regulation of depolarization can indirectly tune vascular tone. This coupling is why GO:1904199 is physiologically meaningful rather than a purely abstract annotation.
Pathological distortion by ion overload and oxidative stress
In simple terms: Fifth, in disease, calcium overload and oxidative stress can disrupt the normal control of depolarization.
Oxidative stress by Ca2+ overload is critical for phosphate-induced vascular calcification, indicating that disturbed Ca2+ handling and oxidative conditions can reprogram vascular smooth muscle behavior. Under such conditions, the regulation of depolarization may be altered, and positive regulation of that regulation may contribute to or compensate for the pathological state. This makes GO:1904199 relevant to vascular calcification research and to models that combine electrophysiology with oxidative stress readouts.
Key Genes Involved in GO:1904199 positive regulation of regulation of vascular associated smooth muscle cell membrane depolarization
The genes and proteins below are experimentally linked to the regulation of vascular smooth muscle membrane depolarization, ion handling or the feedback control of vascular tone, and are therefore candidate entry points for studying GO:1904199.
| Gene | Major Role | Research Relevance |
|---|---|---|
| KCNMA1 | Encodes the BK channel alpha subunit that mediates depolarization-activated feedback | Central to the ROCK-mediated beta1 subunit trafficking mechanism that limits vasoconstriction |
| KCNMB1 | Encodes the BK channel beta1 subunit whose surface trafficking is regulated by ROCK | Directly implicated in the feedback limitation of depolarization and vasoconstriction |
| ROCK1 | Kinase that promotes BK channel beta1 subunit surface trafficking | Modulates the feedback arm that constrains depolarization |
| ROCK2 | ROCK isoform contributing to cytoskeletal and trafficking control | Candidate modifier of BK channel surface availability and depolarization feedback |
| CACNA1C | Voltage-gated calcium channel alpha subunit supporting depolarization-contraction coupling | Relevant to Ca2+ entry that follows membrane depolarization |
| CACNA1D | Voltage-gated calcium channel subunit in vascular smooth muscle | Contributes to Ca2+ handling linked to depolarization and calcification stress |
| SLC8A1 | Na+/Ca2+ exchanger controlling intracellular Ca2+ load | Linked to Ca2+ overload and oxidative stress in vascular calcification |
| ATP2B1 | Plasma membrane Ca2+ ATPase regulating Ca2+ extrusion | Modulates Ca2+ homeostasis that shapes depolarization responses |
| HTR2A | Serotonin receptor mediating agonist-driven electrical changes | Relevant to 5-hydroxytryptamine effects on vascular electrical and mechanical activity |
| HTR1B | Serotonin receptor family member modulating vascular smooth muscle tone | Candidate mediator of agonist-dependent regulation of depolarization |
| ADRA1A | Alpha-1 adrenergic receptor coupled to vascular smooth muscle contraction | Upstream of depolarization and Ca2+ entry in vascular tone control |
| AGTR1 | Angiotensin II receptor modulating vascular smooth muscle excitability | Candidate upstream regulator of depolarization control |
| KCNJ8 | Inward rectifier potassium channel contributing to resting membrane potential | Sets the baseline on which depolarization regulation operates |
| ABCC9 | SUR2 subunit of KATP channels in vascular smooth muscle | Modulates membrane potential and vascular tone |
| CLCN3 | Chloride channel influencing vascular smooth muscle membrane potential | Candidate contributor to the regulation of depolarization |
| TRPC6 | Cation channel linked to vascular smooth muscle Ca2+ and depolarization | Relevant to electromechanical coupling and tone |
| NOS3 | Endothelial nitric oxide synthase modulating vascular smooth muscle tone | Indirect regulator of the depolarization-contraction axis |
| GUCY1A1 | Soluble guanylate cyclase subunit mediating NO signaling in vascular smooth muscle | Downstream modulator of vascular excitability and tone |
How Is positive regulation of regulation of vascular associated smooth muscle cell membrane depolarization Regulated?
The regulation of vascular smooth muscle membrane depolarization is itself regulated at multiple levels. Mechanical tension changes the electrical properties of the smooth muscle membrane, so wall tension acts as a continuous input into the depolarization set point. Agonists such as 5-hydroxytryptamine can shift both electrical and mechanical activity, providing a receptor-mediated input. A key feedback regulator is the BK channel system, in which depolarization activates BK channels through ROCK-mediated beta1 subunit surface trafficking to limit vasoconstriction. In pathological settings, Ca2+ overload and oxidative stress can override normal control and contribute to phosphate-induced vascular calcification. Positive regulation of the regulation of depolarization (GO:1904199) therefore represents processes that increase the gain, sensitivity or strength of these regulatory inputs, rather than the depolarization event itself.
positive regulation of regulation of vascular associated smooth muscle cell membrane depolarization and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| KCNMA1 | Vascular tone and BK channel feedback in vasoconstriction | Knockout or point-mutation vascular smooth muscle cell model with electrophysiology |
| KCNMB1 | Feedback limitation of depolarization and vasoconstriction | Tagged knock-in to track surface trafficking under ROCK modulation |
| SLC8A1 | Ca2+ overload and phosphate-induced vascular calcification | Overexpression and knockout models with oxidative stress readouts |
| HTR2A | Serotonergic modulation of electrical and mechanical activity in vein grafts | Knockout vascular smooth muscle cells with agonist challenge |
| ROCK1 | ROCK-mediated BK channel trafficking and vascular tone | Point-mutation model to separate kinase activity from trafficking effects |
Vascular calcification and Ca2+ overload
Oxidative stress by Ca2+ overload is critical for phosphate-induced vascular calcification, a process in which vascular smooth muscle cells lose normal control of Ca2+ handling and membrane behavior. Because the regulation of depolarization depends on ion gradients and Ca2+ signaling, pathological Ca2+ overload can distort the regulation of depolarization. Genes annotated under GO:1904199 may therefore modify susceptibility to calcification or the cellular response to phosphate stress, making this term relevant to vascular calcification research.
Vasospasm and altered vascular tone
Electrophysiological studies of rat middle cerebral artery show that passive wall tension changes the electrical properties of the smooth muscle membrane, linking mechanical state to depolarization behavior. In conditions such as vasospasm, excessive or poorly regulated depolarization can promote sustained constriction. Positive regulation of the regulation of depolarization could either amplify protective feedback, as seen with BK channel trafficking, or worsen constriction depending on context.
Vein graft remodeling and serotonergic signaling
In rabbit jugular vein grafts, 5-hydroxytryptamine affects electrical and mechanical activities, showing that serotonergic signaling can modulate the regulation of depolarization in remodeled vessels. This has implications for graft adaptation and for understanding how agonist sensitivity changes after vascular surgery. GO:1904199 provides a framework for annotating genes that alter the gain of this serotonergic control.
Hypertension and cardiovascular risk
Because vascular smooth muscle membrane potential is a determinant of arterial tone, processes that positively regulate the regulation of depolarization can influence blood pressure regulation. Feedback mechanisms such as BK channel trafficking limit vasoconstriction and thus oppose excessive tone. When these mechanisms are impaired, the regulation of depolarization may become biased toward constriction, which is relevant to hypertension and related cardiovascular conditions.
From positive regulation of regulation of vascular associated smooth muscle cell membrane depolarization-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of a candidate gene increase or decrease the regulation of depolarization? | CRISPR knockout vascular smooth muscle cell line with membrane potential recordings |
| Does a specific kinase activity domain control BK channel trafficking? | Point-mutation knock-in of the kinase domain |
| Where and when does a candidate protein act during depolarization regulation? | Tagged knock-in with live imaging and electrophysiology |
| Does excess candidate gene product amplify depolarization control? | Overexpression model with tension and electrical recordings |
| Does a disease-associated variant alter Ca2+ handling under phosphate stress? | Knock-in of the variant plus oxidative stress and calcification assays |
| Which upstream receptors modulate the regulation of depolarization? | Knockout of receptor genes followed by agonist challenge |
How to Study the positive regulation of regulation of vascular associated smooth muscle cell membrane depolarization Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Membrane potential recording | Resting and dynamic membrane potential of vascular smooth muscle | Testing whether a gene alters the regulation of depolarization |
| Combined electrical and tension recording | Electromechanical coupling | Linking depolarization regulation to contraction |
| Surface biotinylation or tagged imaging | Plasma membrane trafficking of ion channel subunits | Quantifying BK channel beta1 subunit surface delivery |
| ROCK activity assay | Kinase activity upstream of channel trafficking | Testing whether ROCK inhibition changes depolarization feedback |
| ROS and Ca2+ imaging | Oxidative stress and intracellular Ca2+ load | Modeling phosphate-induced vascular calcification |
| Alizarin red or calcium quantification | Vascular calcification burden | Assessing pathological outcomes of disturbed Ca2+ handling |
| Agonist dose-response electrical recording | Sensitivity to vasoactive agonists | Testing serotonergic modulation of depolarization |
| CRISPR perturbation followed by phenotyping | Causal contribution of a candidate gene | Assigning genes to GO:1904199 |
Electrophysiology of intact vascular smooth muscle
Membrane potential recordings in intact arteries at controlled passive wall tensions allow direct measurement of the electrical state that is being regulated. This approach has been used in rat middle cerebral artery to show tension-dependent changes in smooth muscle electrical properties. For GO:1904199 studies, such recordings provide the primary readout of whether a genetic perturbation changes the regulation of depolarization.
Simultaneous electrical and mechanical recording
Combining electrical recordings with tension measurements captures the electromechanical coupling that links depolarization to contraction. In rabbit jugular vein grafts, 5-hydroxytryptamine was shown to affect both electrical and mechanical activities, demonstrating the value of paired recordings. This method is well suited to testing whether positive regulation of the regulation of depolarization alters vascular tone.
Ion channel trafficking and surface expression assays
Because BK channel beta1 subunit surface trafficking is a key feedback step, assays that measure surface expression and trafficking are essential. ROCK-mediated beta1 subunit surface trafficking was identified as the mechanism by which depolarization activates BK channels to limit vasoconstriction. Tagged knock-in and imaging approaches can quantify this trafficking in living cells.
Oxidative stress and calcification readouts
Phosphate-induced vascular calcification involves oxidative stress by Ca2+ overload, so assays measuring reactive oxygen species, Ca2+ handling and calcification are relevant to GO:1904199. Combining these readouts with electrophysiology helps determine whether pathological Ca2+ overload distorts the regulation of depolarization.
How CRISPR Can Be Used to Study GO:1904199 positive regulation of regulation of vascular associated smooth muscle cell membrane depolarization
Knockout
CRISPR knockout of candidate genes such as KCNMA1, KCNMB1 or ROCK1 in vascular smooth muscle cells allows direct testing of whether the gene is required for the regulation of depolarization. Loss-of-function models can be phenotyped by membrane potential recording and tension measurement, following the logic of studies that linked BK channel trafficking to the limitation of vasoconstriction. Knockout of Ca2+ handling genes can be combined with phosphate stress to assess calcification-related phenotypes.
Point Mutation
Point-mutation models are useful when a specific activity, phosphorylation site or channel property is suspected. For example, mutating kinase domains or trafficking motifs can separate enzymatic activity from channel surface delivery in the ROCK-BK channel axis. Point mutations in Ca2+ handling proteins can test whether a single residue contributes to Ca2+ overload and oxidative stress in calcification models.
Knock-in
Knock-in of tags or disease-associated variants enables tracking of protein localization and function in native chromatin context. Tagged knock-in of BK channel subunits can reveal when and where surface trafficking occurs during depolarization. Knock-in of variants in ion handling genes can be tested under agonist or phosphate stress to see whether the regulation of depolarization is altered.
Overexpression
Overexpression models test whether increasing the amount of a candidate protein amplifies the regulation of depolarization. Overexpressing channel subunits or signaling kinases can shift the gain of the feedback system and change vasoconstrictor responses. Overexpression of Ca2+ handling proteins can also be used to probe oxidative stress and calcification pathways.
How EDITGENE Supports positive regulation of regulation of vascular associated smooth muscle cell membrane depolarization Research
Researchers studying positive regulation of regulation of vascular associated smooth muscle cell membrane depolarization-related genes often need to determine whether a candidate gene is causally involved in setting the gain of depolarization control, rather than merely correlating with it. This requires precise genetic models that can knock out, mutate, tag or overexpress the gene of interest in vascular smooth muscle cells, followed by electrophysiological and mechanical phenotyping.
Contact EDITGENE today to design your custom CRISPR model for positive regulation of regulation of vascular associated smooth muscle cell membrane depolarization research.
Frequently Asked Questions About positive regulation of regulation of vascular associated smooth muscle cell membrane depolarization
What is GO:1904199?
GO:1904199 is the Gene Ontology biological_process term for positive regulation of regulation of vascular associated smooth muscle cell membrane depolarization, meaning any process that activates or increases the frequency, rate or extent of the regulation of vascular smooth muscle cell membrane depolarization.
What does positive regulation of regulation of vascular smooth muscle cell membrane depolarization mean?
It means increasing the strength or gain of the mechanisms that control vascular smooth muscle membrane depolarization, rather than causing depolarization directly.
What genes are involved in the regulation of vascular smooth muscle membrane depolarization?
Genes such as KCNMA1, KCNMB1, ROCK1, ROCK2, CACNA1C, SLC8A1 and HTR2A have been linked to ion handling, channel trafficking or agonist-driven electrical changes in vascular smooth muscle.
How is vascular smooth muscle membrane depolarization measured?
It is measured by electrophysiological recording of membrane potential in intact arteries or isolated cells, often combined with tension measurements to capture electromechanical coupling.
Why does wall tension affect vascular smooth muscle electrical properties?
Electrophysiological studies of rat middle cerebral artery show that different levels of passive wall tension change the electrical properties of the smooth muscle membrane, indicating that mechanical state is an input into depolarization control.
What role do BK channels play in limiting vasoconstriction?
Depolarization activates BK channels through ROCK-mediated beta1 subunit surface trafficking, which limits vasoconstriction and acts as a feedback brake on depolarization.
How does serotonin affect vascular smooth muscle electrical activity?
In rabbit jugular vein grafts, 5-hydroxytryptamine affects both electrical and mechanical activities, showing that serotonergic signaling can modulate the regulation of depolarization.
Is Ca2+ overload relevant to vascular calcification?
Yes, oxidative stress by Ca2+ overload is critical for phosphate-induced vascular calcification, linking disturbed Ca2+ handling to vascular pathology.
What CRISPR models are useful for studying GO:1904199?
Knockout, point-mutation, knock-in and overexpression models in vascular smooth muscle cells are all useful, followed by membrane potential recording and tension assays.
How can EDITGENE help with GO:1904199 research?
EDITGENE provides knockout, point-mutation, knock-in, overexpression, CRISPR library screening and bioinformatics services to test causal roles of candidate genes in the regulation of vascular smooth muscle depolarization.
Conclusion
GO:1904199 captures a second-order regulatory process: the positive control of the regulation of vascular associated smooth muscle cell membrane depolarization. Experimental work shows that this regulation is real and measurable, with inputs from wall tension, vasoactive agonists and feedback mechanisms such as ROCK-mediated BK channel trafficking. Pathological states involving Ca2+ overload and oxidative stress can distort these controls and contribute to vascular calcification. By combining precise CRISPR models with electrophysiology and molecular readouts, researchers can assign genes to this term and clarify how the gain of depolarization control is set in health and disease.
References
- 1. Leo MD et al.. 2017. Membrane depolarization activates BK channels through ROCK-mediated β1 subunit surface trafficking to limit vasoconstriction.. Sci Signal 10(478) PMID: 28487419
- 2. Nguyen NT et al.. 2020. Oxidative stress by Ca(2+) overload is critical for phosphate-induced vascular calcification.. Am J Physiol Heart Circ Physiol 319(6):H1302-H1312 PMID: 33095057
- 3. McPherson GA et al.. 1995. Electrophysiological properties of the rat middle cerebral artery at different levels of passive wall tension.. Clin Exp Pharmacol Physiol 22(10):724-31 PMID: 8575108
- 4. Maekawa T et al.. 2012. Characteristics of the actions by which 5-hydroxytryptamine affects electrical and mechanical activities in rabbit jugular vein graft.. Br J Pharmacol 166(4):1419-32 PMID: 22251164
