GO:0050115 myosin-light-chain-phosphatase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0050115 myosin-light-chain-phosphatase activity describes the enzymatic removal of phosphate from myosin light chains, a reaction that directly opposes myosin light chain kinase and controls myosin motor activity.
• The holoenzyme is a trimeric complex of a catalytic PP1c subunit, a MYPT regulatory subunit, and a small M20 subunit, and its substrate specificity and localization depend on the MYPT isoform.
• MYPT1-containing myosin light chain phosphatase predominates in smooth muscle and non-muscle cells, whereas MYPT2-containing phosphatase is striated-muscle-specific and limits cardiac myosin phosphorylation in vivo.
• Rho-kinase inhibits myosin light chain phosphatase by phosphorylating MYPT1, thereby increasing myosin light chain phosphorylation and promoting contraction, a mechanism implicated in endothelin-1-induced TGF-beta receptor transactivation.
• Altered myosin light chain phosphatase activity contributes to cardiac hypertrophy, heart failure, airway hyperresponsiveness, and platelet dysfunction, making it a candidate target for experimental therapeutics.
• CRISPR knockout, point-mutation, knock-in, and overexpression models enable causal dissection of MYPT and PP1c subunit contributions to myosin light chain phosphatase function in health and disease.
Description
Myosin light chain phosphatase (MLCP) is the enzyme that catalyzes the removal of phosphate from the regulatory light chain of myosin II, a reaction formally described by the Gene Ontology term GO:0050115 myosin-light-chain-phosphatase activity. This phosphatase activity is the biochemical counterweight to myosin light chain kinase (MLCK), and the balance between these two activities sets the phosphorylation state of myosin light chains, which in turn governs myosin ATPase activity, actin filament sliding, and contractile force in smooth muscle and non-muscle cells. Because myosin light chain phosphorylation is a central switch for contraction, cell migration, cytokinesis, and platelet shape change, the phosphatase that reverses this modification is a focal point for research in cardiovascular biology, respiratory disease, and hemostasis. The catalytic activity itself is carried out by a protein phosphatase 1 catalytic subunit (PP1c), but the enzyme functions as a holoenzyme in which a myosin phosphatase target subunit (MYPT) and a small M20 subunit confer substrate specificity, subcellular targeting, and regulatory responsiveness. Distinct MYPT genes and splice variants produce MLCP complexes with different tissue distributions and kinetic properties, and this diversity explains why the same catalytic activity can serve different physiological roles in smooth muscle, cardiac muscle, and platelets. For researchers, GO:0050115 provides a precise annotation for experiments that measure phosphate release from myosin light chains, and it links those measurements to a defined molecular function that can be manipulated genetically and pharmacologically.
myosin-light-chain-phosphatase activity At A Glance
| GO ID | GO:0050115 |
|---|---|
| GO term | myosin-light-chain-phosphatase activity |
| Ontology | molecular_function |
| Synonym | myosin light chain kinase phosphatase activity; myosin-light-chain kinase phosphatase activity; myosin-light-chain phosphatase activity; [Myosin light-chain]-phosphatase activity; myosin-light-chain-phosphate phosphohydrolase activity; protein phosphatase 2A |
| Major function | Catalyzes the dephosphorylation of myosin light chains, opposing myosin light chain kinase and regulating myosin II contractile activity |
| Reaction | myosin light-chain phosphate + H2O = myosin light chain + phosphate |
| Core subunits | PP1c catalytic subunit, MYPT regulatory subunit, M20 small subunit |
| Tissue variants | MYPT1-containing smooth muscle/non-muscle MLCP; MYPT2-containing striated muscle MLCP |
| Regulation | Inhibited by Rho-kinase-mediated phosphorylation of MYPT1; modulated by arachidonic acid, cyclic nucleotides, and subunit interactions |
What Is GO:0050115?
GO:0050115 myosin-light-chain-phosphatase activity is defined as catalysis of the reaction: myosin light-chain phosphate + H2O = myosin light chain + phosphate. In practical terms, it is the hydrolase activity that removes a phosphate group from a phosphorylated myosin light chain substrate, releasing free phosphate and regenerating the unphosphorylated myosin light chain. The term is a molecular_function annotation and is synonymous with myosin light chain kinase phosphatase activity, myosin-light-chain kinase phosphatase activity, myosin-light-chain phosphatase activity, [myosin light-chain]-phosphatase activity, myosin-light-chain-phosphate phosphohydrolase activity, and protein phosphatase 2A in the QuickGO synonym set. The activity is typically measured as the release of inorganic phosphate from phosphorylated myosin light chains or as the dephosphorylation of myosin light chains in intact or permeabilized contractile systems.
Why Is myosin-light-chain-phosphatase activity Important in Cell Biology?
GO:0050115 is important because the phosphorylation state of myosin light chains is a final common determinant of contractility, motility, and cytokinesis, and the phosphatase activity encoded by this term is the only enzymatic activity that directly reverses myosin light chain phosphorylation. In smooth muscle, inhibition of MLCP by Rho-kinase produces calcium sensitization, a phenomenon in which contractile force increases without a rise in intracellular calcium, and this mechanism contributes to airway hyperresponsiveness, vascular tone, and endothelin-1 signaling. In the heart, MYPT2-regulated MLCP limits cardiac myosin phosphorylation in vivo, and loss of this restraint is linked to hypertrophic signaling and heart failure. In platelets, MLCP controls shape change and granule secretion, and its dysregulation has been associated with thrombotic phenotypes. Because the activity is enzymatically defined and genetically tractable, it is a high-value target for studies that seek to separate the contributions of catalytic subunits, regulatory subunits, and upstream kinases in human disease.
• Sets the phosphorylation state of myosin light chains, the primary switch for smooth muscle and non-muscle contraction.
• Mediates calcium sensitization when inhibited by Rho-kinase, linking G-protein-coupled receptor signaling to force generation.
• Limits cardiac myosin phosphorylation in vivo through MYPT2-containing complexes, with implications for hypertrophy and heart failure.
• Regulates platelet shape change and secretion, connecting the activity to hemostasis and thrombosis.
• Contributes to airway smooth muscle hyperresponsiveness in asthma models, as shown in sensitized canine tracheal smooth muscle.
• Provides a druggable node for vasodilators, bronchodilators, and antiplatelet strategies.
• Serves as a biochemical readout for myosin light chain kinase versus phosphatase balance in cell migration and cytokinesis studies.
• Enables genetic dissection of MYPT1 versus MYPT2 functions using knockout and knock-in models.
• Links endothelin-1 signaling to TGF-beta receptor transactivation, bridging contractile and fibrotic pathways.
• Offers a defined molecular function annotation for high-throughput screens of phosphatase modulators.
Molecular Mechanism of myosin-light-chain-phosphatase activity
Substrate recognition and holoenzyme assembly
In simple terms: The phosphatase only works on myosin light chains because a targeting subunit holds it in the right place.
Myosin light chain phosphatase is a holoenzyme composed of a PP1c catalytic subunit, a MYPT regulatory subunit, and a small M20 subunit. The MYPT subunit binds the phosphorylated myosin light chain substrate and anchors the complex to myosin, thereby conferring substrate specificity that the isolated PP1c catalytic subunit lacks. Different MYPT isoforms direct the complex to different tissues: MYPT1 is broadly expressed in smooth muscle and non-muscle cells, whereas MYPT2 is striated-muscle-specific and limits cardiac myosin phosphorylation in vivo.
Catalytic dephosphorylation of myosin light chains
In simple terms: The enzyme removes a phosphate tag from myosin, turning off the signal that makes the motor protein active.
The catalytic reaction follows the general mechanism of protein serine/threonine phosphatases: a metal-activated water molecule attacks the phosphorus atom of the phosphoserine or phosphothreonine residue on the myosin light chain, releasing inorganic phosphate and regenerating the unphosphorylated light chain. The reaction is reversible in principle but physiologically driven toward dephosphorylation by the high cellular concentration of myosin light chain substrate and by the continuous activity of myosin light chain kinase. The catalytic subunit can dephosphorylate cardiac myosin via mechanisms that are both dependent and independent of the MYPT regulatory subunits, indicating that regulatory subunit availability modulates but does not absolutely determine activity.
Regulation by Rho-kinase and upstream signals
In simple terms: Other enzymes can put a brake on the phosphatase, keeping myosin phosphorylated and the muscle contracted.
Rho-kinase phosphorylates the MYPT1 subunit at inhibitory sites, which suppresses myosin light chain phosphatase activity and increases myosin light chain phosphorylation without a change in intracellular calcium, a phenomenon known as calcium sensitization. In endothelin-1-stimulated cells, myosin light chain phosphatase is a downstream target of Rho-kinase during transactivation of the TGF-beta receptor, linking contractile signaling to fibrotic gene expression. Additional regulation occurs through arachidonic acid, cyclic GMP-dependent pathways, and interactions with inhibitory proteins, all of which tune the phosphatase in a cell-type-specific manner.
Physiological consequences in muscle and non-muscle cells
In simple terms: By controlling myosin phosphorylation, this phosphatase decides how hard a muscle cell pulls and how a non-muscle cell moves.
In smooth muscle, myosin light chain phosphatase activity opposes myosin light chain kinase and promotes relaxation; its inhibition by Rho-kinase sustains contraction. In cardiac muscle, MYPT2-regulated phosphatase limits cardiac myosin phosphorylation in vivo, and this restraint is important for normal cardiac physiology and for preventing pathological hypertrophy. In platelets, the phosphatase keeps myosin light chain phosphorylation in check and thereby modulates shape change and granule secretion. In airway smooth muscle from sensitized animals, altered myosin light chain phosphatase activity has been observed, suggesting a role in hyperresponsiveness.
Measurement and experimental manipulation
In simple terms: Scientists can measure this activity by tracking phosphate release or by watching myosin phosphorylation in cells.
Myosin light chain phosphatase activity is commonly measured as the release of inorganic phosphate from phosphorylated myosin light chains or as the loss of phospho-myosin light chain signal in Western blots of cells and tissues. Genetic manipulation of MYPT and PP1c subunits, including knockout and knock-in approaches, allows researchers to attribute specific functions to individual subunits and to test whether a candidate gene is causally involved in a phenotype. Pharmacological inhibitors such as okadaic acid and calyculin A are used to block phosphatase activity in intact preparations, although their specificity must be interpreted with care.
Key Genes Involved in GO:0050115 myosin-light-chain-phosphatase activity
The genes and proteins below encode the catalytic and regulatory subunits of myosin light chain phosphatase or its principal upstream regulators, and each has been experimentally linked to the activity described by GO:0050115.
| Gene | Major Role | Research Relevance |
|---|---|---|
| PPP1CA | PP1c catalytic subunit alpha; carries out the dephosphorylation reaction | Core catalytic activity; knockout reduces total MLCP activity |
| PPP1CB | PP1c catalytic subunit beta; alternative catalytic isoform | Isoform-specific contributions to myosin dephosphorylation |
| PPP1CC | PP1c catalytic subunit gamma; alternative catalytic isoform | Tissue-specific roles in contractile regulation |
| PPP1R12A | MYPT1 regulatory subunit; targets PP1c to myosin and mediates Rho-kinase inhibition | Central regulator of smooth muscle calcium sensitization |
| PPP1R12B | MYPT2 regulatory subunit; striated muscle-specific targeting subunit | Limits cardiac myosin phosphorylation in vivo |
| PPP1R12C | MYPT3-related regulatory subunit; modulates phosphatase targeting | Less characterized; potential isoform-specific functions |
| PPP1R14A | CPI-17 inhibitory protein; inhibits MLCP when phosphorylated | Links protein kinase C signaling to calcium sensitization |
| MYLK | Myosin light chain kinase; phosphorylates myosin light chains | Opposing enzyme that sets the phosphorylation balance |
| ROCK1 | Rho-kinase 1; phosphorylates MYPT1 and inhibits MLCP | Upstream inhibitor in endothelin-1 and TGF-beta signaling |
| ROCK2 | Rho-kinase 2; phosphorylates MYPT1 and inhibits MLCP | Isoform-specific regulation of contractility |
| MYH9 | Non-muscle myosin heavy chain IIA; substrate-binding partner | Links MLCP to non-muscle contractile structures |
| MYH10 | Non-muscle myosin heavy chain IIB; substrate-binding partner | Roles in cytokinesis and cell migration |
| MYL9 | Smooth muscle myosin regulatory light chain; direct substrate | Phosphorylation readout for MLCP activity |
| MYL12A | Non-muscle myosin regulatory light chain; direct substrate | Substrate for MLCP in non-muscle cells |
| MYL12B | Non-muscle myosin regulatory light chain; direct substrate | Substrate for MLCP in non-muscle cells |
| EDN1 | Endothelin-1; upstream agonist that activates Rho-kinase and inhibits MLCP | Links vasoactive signaling to phosphatase regulation |
| TGFBR1 | TGF-beta receptor 1; transactivated downstream of endothelin-1 and MLCP inhibition | Connects MLCP to fibrotic signaling |
How Is myosin-light-chain-phosphatase activity Regulated?
Myosin light chain phosphatase activity is regulated at multiple levels. The best-characterized mechanism is inhibitory phosphorylation of the MYPT1 regulatory subunit by Rho-kinase, which suppresses phosphatase activity and promotes calcium sensitization in smooth muscle. Phosphorylation of CPI-17 by protein kinase C similarly inhibits the holoenzyme and contributes to agonist-induced contraction. Cyclic GMP-dependent pathways can enhance phosphatase activity or reduce calcium sensitivity, providing a counter-regulatory brake. In the heart, MYPT2-containing phosphatase is regulated in a striated-muscle-specific manner and limits cardiac myosin phosphorylation in vivo, and its loss is associated with pathological remodeling. Subunit composition itself is a regulatory layer: the catalytic PP1c subunit can dephosphorylate cardiac myosin through mechanisms that are both dependent and independent of MYPT subunits, so the availability of regulatory subunits sets the ceiling for regulated activity. Finally, arachidonic acid and other lipid mediators can modulate phosphatase activity, and platelet MLCP is subject to regulation by platelet agonists and cyclic nucleotides.
myosin-light-chain-phosphatase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| PPP1R12B | Cardiac hypertrophy and heart failure | Cardiomyocyte-specific knockout and MYPT2 knock-in mice |
| PPP1R12A | Vascular tone, hypertension, fibrosis | Smooth muscle cell knockout and phospho-mutant knock-in |
| PPP1R14A | Airway hyperresponsiveness and asthma | Airway smooth muscle overexpression of CPI-17 |
| PPP1CA | Platelet dysfunction and thrombosis | Platelet-specific PP1c knockout |
| ROCK1/ROCK2 | Endothelin-1-driven TGF-beta transactivation | Rho-kinase inhibitor treatment combined with MYPT1 point mutation |
Cardiac hypertrophy and heart failure
MYPT2-regulated myosin light chain phosphatase limits cardiac myosin phosphorylation in vivo, and disruption of this restraint is linked to pathological cardiac remodeling. The role of MLCP in cardiac physiology and pathophysiology has been reviewed in detail, with evidence that altered phosphatase activity contributes to hypertrophic signaling and contractile dysfunction. Because cardiac myosin phosphorylation is a direct readout of the balance between myosin light chain kinase and MLCP, experimental models that manipulate MYPT2 or PP1c subunits can test whether restoring phosphatase activity is protective.
Airway hyperresponsiveness and asthma
In ragweed pollen-sensitized canine tracheal smooth muscle, myosin light chain phosphatase activity was measured and found to be altered relative to control tissue, suggesting a contribution to airway hyperresponsiveness. Rho-kinase-mediated inhibition of MLCP is a well-established mechanism of calcium sensitization in airway smooth muscle, and this pathway is a target for bronchodilator strategies. Experimental models that measure phosphatase activity in sensitized versus naive airway smooth muscle can define the causal contribution of GO:0050115 to asthma phenotypes.
Vascular disease and fibrosis
Endothelin-1 activates Rho-kinase, which inhibits myosin light chain phosphatase and promotes transactivation of the TGF-beta receptor, linking contractile signaling to fibrotic gene expression in vascular cells. This mechanism places MLCP at the intersection of vasoconstriction and tissue remodeling, and it suggests that modulating phosphatase activity could influence both vascular tone and fibrosis. Experimental systems that combine endothelin-1 stimulation with MYPT1 knockdown or knock-in of phospho-deficient MYPT1 can isolate the phosphatase-dependent component of TGF-beta transactivation.
Platelet dysfunction and thrombosis
Platelet myosin light chain phosphatase controls shape change and granule secretion, and its regulation is important for normal hemostasis. Because platelet activation involves rapid changes in myosin light chain phosphorylation, altered MLCP activity could contribute to thrombotic or bleeding phenotypes. Platelet-specific knockout or knock-in models of MYPT1 and PP1c subunits provide a way to test the role of GO:0050115 in platelet function in vivo.
From myosin-light-chain-phosphatase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of MYPT2 increase cardiac myosin phosphorylation in vivo? | MYPT2 knockout mouse with cardiac phospho-myosin light chain readout |
| Is PP1c catalytic activity required for smooth muscle relaxation? | Smooth muscle-specific PP1c knockout or point-mutation knock-in |
| Does phospho-deficient MYPT1 block Rho-kinase-mediated calcium sensitization? | MYPT1 phospho-site point mutation knock-in |
| Can tagged MYPT1 track holoenzyme localization in live cells? | Tagged knock-in of MYPT1 with fluorescent or epitope tag |
| Does overexpression of CPI-17 inhibit MLCP and promote contraction? | Inducible CPI-17 overexpression in smooth muscle cells |
| Which MYPT isoform controls platelet shape change? | Platelet-specific MYPT1 or MYPT2 knockout |
How to Study the myosin-light-chain-phosphatase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Malachite green phosphate assay | Inorganic phosphate released from phosphorylated myosin light chains | Direct MLCP activity measurement in immunoprecipitates |
| Phospho-myosin light chain Western blot | Phosphorylation state of myosin light chains | Readout of MLCP versus MLCK balance in cells and tissues |
| Immunofluorescence microscopy | Subcellular localization of MYPT and phospho-myosin light chain | Spatial organization of MLCP at contractile structures |
| Rho-kinase inhibitor treatment | Relief of inhibitory MYPT1 phosphorylation | Distinguishing upstream regulation from catalytic activity |
| Smooth muscle contraction assay | Force generation in response to agonists | Functional consequence of MLCP modulation |
| Platelet shape change assay | Morphological and secretory response of platelets | Role of MLCP in hemostasis |
| CRISPR knockout and knock-in | Causal contribution of specific subunits | Genetic dissection of MLCP function |
| Co-immunoprecipitation | Subunit composition of MLCP holoenzyme | Defining PP1c-MYPT-M20 complexes |
Phosphatase activity assays
Direct measurement of GO:0050115 uses phosphorylated myosin light chains as substrate and quantifies released inorganic phosphate by colorimetric or radioactive methods. These assays can be performed on immunoprecipitated MLCP complexes to attribute activity to specific subunit compositions, and they are the gold standard for confirming that a genetic manipulation changes catalytic activity rather than just protein abundance.
Phospho-protein immunoblotting and imaging
Western blotting with phospho-specific antibodies against myosin light chain residues reports the balance between myosin light chain kinase and MLCP in cells and tissues. Immunofluorescence imaging of phospho-myosin light chain and MYPT subunits reveals spatial organization of the activity at contractile structures, and live-cell imaging with tagged subunits can track holoenzyme dynamics.
Genetic and pharmacological perturbation
Knockout, knockdown, point-mutation, and overexpression approaches are used to test causality, while pharmacological inhibitors such as okadaic acid and calyculin A provide acute blockade of phosphatase activity. Rho-kinase inhibitors are used to relieve inhibitory phosphorylation of MYPT1 and thereby activate MLCP, allowing researchers to distinguish upstream regulation from catalytic capacity.
Functional contractility and motility readouts
Because GO:0050115 controls myosin-driven force, functional assays such as smooth muscle contraction, airway narrowing, platelet shape change, and cell migration are used as downstream readouts. Combining these functional assays with phospho-myosin light chain measurements establishes a causal chain from phosphatase activity to phenotype.
How CRISPR Can Be Used to Study GO:0050115 myosin-light-chain-phosphatase activity
Knockout
CRISPR knockout of PPP1CA, PPP1CB, PPP1CC, PPP1R12A, or PPP1R12B eliminates specific MLCP subunits and allows researchers to measure the resulting change in myosin light chain phosphorylation and contractile phenotype. Because PP1c subunits are shared with other phosphatases, tissue-specific and isoform-specific knockouts are preferred to avoid confounding developmental effects.
Point Mutation
Point mutation of the Rho-kinase phosphorylation sites in MYPT1 or of catalytic residues in PP1c can separate regulatory from catalytic functions of GO:0050115. Phospho-deficient MYPT1 knock-in models are particularly useful for testing whether calcium sensitization depends on inhibitory phosphorylation of the regulatory subunit.
Knock-in
Knock-in of epitope-tagged or fluorescently tagged MYPT1, MYPT2, or PP1c subunits enables live-cell tracking of holoenzyme localization and interaction dynamics without altering endogenous expression levels. Knock-in of disease-associated variants can also test whether specific mutations alter phosphatase activity or subunit assembly.
Overexpression
Overexpression of wild-type or mutant MYPT subunits, PP1c subunits, or the inhibitory protein CPI-17 can acutely increase or decrease MLCP activity and reveal downstream consequences for myosin phosphorylation and contraction. Inducible overexpression systems are preferred when constitutive high-level expression would cause developmental lethality or compensatory adaptation.
How EDITGENE Supports myosin-light-chain-phosphatase activity Research
Researchers studying myosin-light-chain-phosphatase activity-related genes often need to determine whether a candidate gene is causally involved in a contractile or disease phenotype, and this requires precise genetic models that isolate the contribution of individual subunits, catalytic residues, and regulatory phosphorylation sites. EDITGENE provides end-to-end CRISPR services that generate these models in relevant cell types and animal backgrounds, enabling direct tests of GO:0050115 function.
Contact EDITGENE today to design your custom CRISPR model for myosin-light-chain-phosphatase activity research.
Frequently Asked Questions About myosin-light-chain-phosphatase activity
What is myosin-light-chain-phosphatase activity?
It is the enzymatic activity defined by GO:0050115 that removes phosphate from myosin light chains, reversing the action of myosin light chain kinase and thereby regulating myosin-driven contraction and motility.
What genes are involved in myosin-light-chain-phosphatase activity?
The core genes include PPP1CA, PPP1CB, and PPP1CC encoding PP1c catalytic subunits, PPP1R12A and PPP1R12B encoding MYPT1 and MYPT2 regulatory subunits, and upstream regulators such as ROCK1, ROCK2, and PPP1R14A.
How is myosin-light-chain-phosphatase activity regulated?
It is inhibited by Rho-kinase-mediated phosphorylation of MYPT1 and by CPI-17, and it is modulated by cyclic nucleotides, arachidonic acid, and subunit composition.
What is the role of myosin light chain phosphatase in smooth muscle contraction?
It opposes myosin light chain kinase and promotes relaxation; its inhibition produces calcium sensitization and sustained contraction.
How does myosin light chain phosphatase affect the heart?
MYPT2-containing phosphatase limits cardiac myosin phosphorylation in vivo, and its dysregulation is linked to cardiac hypertrophy and heart failure.
Is myosin light chain phosphatase involved in asthma?
Altered phosphatase activity has been observed in sensitized airway smooth muscle, and Rho-kinase-mediated inhibition of MLCP contributes to airway hyperresponsiveness.
What is the difference between MYPT1 and MYPT2?
MYPT1 is broadly expressed in smooth muscle and non-muscle cells, whereas MYPT2 is striated-muscle-specific and regulates cardiac myosin phosphorylation.
How can I measure myosin-light-chain-phosphatase activity in the lab?
Common methods include phosphate release assays using phosphorylated myosin light chains, phospho-myosin light chain Western blots, and functional contractility assays.
Can CRISPR be used to study myosin-light-chain-phosphatase activity?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models allow causal testing of individual MLCP subunits and regulatory sites.
What diseases are associated with myosin light chain phosphatase dysfunction?
Cardiac hypertrophy, heart failure, airway hyperresponsiveness, vascular fibrosis, and platelet dysfunction have been linked to altered MLCP activity.
Conclusion
GO:0050115 myosin-light-chain-phosphatase activity defines a central enzymatic counterweight to myosin light chain kinase, and its regulation by MYPT subunits, Rho-kinase, and CPI-17 controls contractility in smooth muscle, cardiac muscle, platelets, and non-muscle cells. The activity is implicated in cardiac hypertrophy, airway hyperresponsiveness, vascular fibrosis, and platelet dysfunction, making it a compelling target for mechanistic and translational studies. Advances in CRISPR-based knockout, point-mutation, knock-in, and overexpression models now allow researchers to dissect the precise contributions of catalytic and regulatory subunits to this activity in health and disease.
References
- 1. Lee E et al.. 2022. Myosin light chain phosphatase catalytic subunit dephosphorylates cardiac myosin via mechanisms dependent and independent of the MYPT regulatory subunits.. J Biol Chem 298(9):102296 PMID: 35872014
- 2. Hartshorne DJ et al.. 1998. Myosin light chain phosphatase: subunit composition, interactions and regulation.. J Muscle Res Cell Motil 19(4):325-41 PMID: 9635276
- 3. Rezaei M et al.. 2024. Myosin light chain phosphatase is a downstream target of Rho-kinase in endothelin-1-induced transactivation of the TGF-β receptor.. Cell Biochem Biophys 82(2):1109-1120 PMID: 38834831
- 4. Lee E et al.. 2024. The MYPT2-regulated striated muscle-specific myosin light chain phosphatase limits cardiac myosin phosphorylation in vivo.. J Biol Chem 300(2):105652 PMID: 38224947
- 5. Chang AN et al.. 2016. Role of myosin light chain phosphatase in cardiac physiology and pathophysiology.. J Mol Cell Cardiol 101:35-43 PMID: 27742556
- 6. Aburima A et al.. 2014. Platelet myosin light chain phosphatase: keeping it together.. Biochem Soc Trans 42(2):279-83 PMID: 24646231
- 7. Brozovich FV. 2002. Myosin light chain phosphatase: it gets around.. Circ Res 90(5):500-2 PMID: 11909811
- 8. Liu X et al.. 1994. Myosin light chain phosphatase activity in ragweed pollen-sensitized canine tracheal smooth muscle.. Am J Respir Cell Mol Biol 11(6):676-81 PMID: 7946396
