GO:0046935 1-phosphatidylinositol-3-kinase regulator activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0046935 describes a molecular function that modulates the activity of the enzyme 1-phosphatidylinositol-3-kinase (PI3K), rather than the catalytic lipid kinase activity itself.
• Regulators of PI3K include proteins such as PIK3R1 (p85α), PIK3R2, PIK3R3, and other subunits that control PI3K signaling output in response to receptor tyrosine kinase and G-protein-coupled receptor activation [1,6].
• Dysregulation of PI3K regulator activity is implicated in cancer, cardiac disease, metabolic disorders, and neurological conditions [1,3,8].
• The PI3K/AKT pathway, which is controlled by PI3K regulators, is one of the most frequently altered signaling cascades in human cancers [1,8].
• Experimental models for studying GO:0046935 include CRISPR knockout, point-mutation knock-in, and overexpression of regulatory subunits in cell lines and animal models [3,4].
• EDITGENE provides CRISPR-based services to dissect the function of PI3K regulators, including KO, point mutation, knock-in, overexpression, and library screening.
Description
The Gene Ontology (GO) term GO:0046935, 1-phosphatidylinositol-3-kinase regulator activity, defines a molecular function that modulates the activity of the enzyme 1-phosphatidylinositol-3-kinase (PI3K). This term is distinct from the catalytic activity of PI3K itself; it specifically captures the regulatory inputs that control when, where, and how strongly PI3K signals [1,6]. PI3K signaling is central to diverse cellular processes, including growth, survival, proliferation, and metabolism, and its regulators are critical for maintaining normal physiology [1,6]. Researchers study GO:0046935 to understand how extracellular cues are translated into intracellular lipid signals. The regulatory subunits of class I PI3Ks, such as PIK3R1 (p85α), are the prototypical proteins annotated with this function. These regulators integrate signals from receptor tyrosine kinases and G-protein-coupled receptors to activate the catalytic subunit (e.g., PIK3CA). Dysregulation of this regulatory function is linked to cancer, cardiac hypertrophy, and metabolic disease, making it a high-priority target for therapeutic intervention [1,3,8]. In this article, we provide a comprehensive overview of GO:0046935, covering its definition, biological significance, key genes, regulatory mechanisms, disease associations, and experimental approaches for studying it. All statements are based on published literature and the QuickGO definition.
1-phosphatidylinositol-3-kinase regulator activity At A Glance
| GO ID | GO:0046935 |
|---|---|
| GO term | 1-phosphatidylinositol-3-kinase regulator activity |
| Ontology | molecular_function |
| Synonym | 1-phosphatidylinositol 3-kinase regulator activity; phosphatidylinositol 3-kinase, class I, regulator activity |
| Major function | Modulates the activity of the enzyme 1-phosphatidylinositol-3-kinase (PI3K) |
| Related enzyme | 1-phosphatidylinositol-3-kinase (PI3K) |
| Example regulators | PIK3R1 (p85α), PIK3R2 (p85β), PIK3R3 (p55γ), PIK3R5, PIK3R6 |
| Pathway context | PI3K/AKT signaling pathway |
| Disease relevance | Cancer, cardiac disease, metabolic disorders, neurological conditions |
What Is GO:0046935?
According to the Gene Ontology, GO:0046935 (1-phosphatidylinositol-3-kinase regulator activity) is a molecular function that modulates the activity of the enzyme 1-phosphatidylinositol-3-kinase. In other words, it is the function of proteins that regulate PI3K, rather than the function of PI3K itself. This term encompasses both positive and negative regulation of PI3K catalytic activity, and it is often associated with regulatory subunits such as PIK3R1, PIK3R2, and PIK3R3 [1,6].
Why Is 1-phosphatidylinositol-3-kinase regulator activity Important in Cell Biology?
GO:0046935 is important because it governs the activity of PI3K, a central node in cell signaling that controls cell growth, survival, and metabolism. The PI3K/AKT pathway is one of the most frequently dysregulated pathways in human cancer, and regulatory subunits such as PIK3R1 are recurrently mutated or altered in various malignancies [1,8]. Beyond cancer, PI3K regulators are implicated in cardiac hypertrophy, atrial fibrillation, skeletal muscle atrophy, and metabolic disorders [3,4,5]. Understanding how these regulators function at the molecular level can reveal new therapeutic targets and biomarkers for a wide range of diseases.
• Controls PI3K/AKT signaling, a master regulator of cell growth and survival.
• Mutations in PI3K regulatory subunits (e.g., PIK3R1) are found in cancers such as glioblastoma and colorectal cancer [1,8].
• PI3K regulators are involved in cardiac physiology; reduced PI3K(p110α) activity leads to atrial myopathy.
• Exercise-induced skeletal muscle adaptation requires IGF-1/IGF-1R-PI3K/Akt signaling, which is modulated by PI3K regulators.
• Regulation of PI3K is essential for insulin signaling and glucose homeostasis.
• Class III PI3K (Vps34) regulators control autophagy and vesicular trafficking.
• PI3K regulators are targets for drug development in oncology and cardiology [1,3].
• Studying GO:0046935 helps dissect the specificity of PI3K signaling in different cellular contexts [1,6].
• CRISPR-based models of PI3K regulators enable functional validation of disease-associated variants [3,4].
What Happens During 1-phosphatidylinositol-3-kinase regulator activity?
Receptor-mediated activation of PI3K
In simple terms: When a growth factor binds to its receptor, the receptor activates PI3K with the help of regulatory proteins.
In response to extracellular signals such as growth factors or insulin, receptor tyrosine kinases (RTKs) autophosphorylate and create docking sites for the regulatory subunit of class I PI3K, typically PIK3R1 (p85α). This interaction relieves the inhibitory effect of the regulatory subunit on the catalytic subunit (e.g., PIK3CA), leading to PI3K activation and production of phosphatidylinositol-3,4,5-trisphosphate (PIP3). This process is a key example of GO:0046935, where the regulatory subunit modulates the enzyme's activity.
G-protein-coupled receptor (GPCR) regulation of PI3K
In simple terms: Some G-protein-coupled receptors can also activate PI3K through direct binding of Gβγ subunits to the regulatory subunit.
GPCRs can activate PI3Kβ and PI3Kγ isoforms via direct interaction with Gβγ subunits, which bind to the regulatory subunits or the catalytic subunit itself. This alternative mode of regulation highlights the diversity of inputs that converge on PI3K and the importance of GO:0046935 in integrating signals from different receptor classes.
Negative regulation by phosphatases and lipid phosphatases
In simple terms: Enzymes like PTEN remove the phosphate groups that PI3K adds, shutting down the signal.
The lipid phosphatase PTEN dephosphorylates PIP3 to PIP2, directly antagonizing PI3K activity. While PTEN is not a regulator of PI3K per se, it is a critical negative regulator of the pathway. Additionally, proteins such as PIK3IP1 can negatively regulate PI3K by interacting with the catalytic subunit. These mechanisms ensure that PI3K signaling is tightly controlled, and their dysregulation contributes to disease.
Regulation by phosphorylation and post-translational modifications
In simple terms: PI3K regulatory subunits can be modified by phosphorylation, which changes their ability to control PI3K.
The regulatory subunit p85α is subject to phosphorylation by various kinases, including Src and Abl, which can modulate its interaction with the catalytic subunit and its localization. These post-translational modifications fine-tune PI3K activity in response to cellular stress and other signals, adding another layer of complexity to GO:0046935.
Key Genes Involved in GO:0046935 1-phosphatidylinositol-3-kinase regulator activity
The following genes encode proteins that possess or are directly associated with 1-phosphatidylinositol-3-kinase regulator activity (GO:0046935) or are key components of the PI3K regulatory complex.
| Gene | Major Role | Research Relevance |
|---|---|---|
| PIK3R1 | Encodes p85α, the predominant regulatory subunit of class IA PI3K; stabilizes and inhibits the catalytic subunit | Frequently mutated in cancer; essential for insulin signaling [1,2] |
| PIK3R2 | Encodes p85β, a regulatory subunit with overlapping and distinct functions from p85α | Implicated in cancer and developmental disorders |
| PIK3R3 | Encodes p55γ, a regulatory subunit that can modulate PI3K activity | Studied in cancer and neuronal signaling |
| PIK3R5 | Encodes p101, a regulatory subunit for class IB PI3Kγ | Important for GPCR-mediated PI3K activation in immune cells |
| PIK3R6 | Encodes p84, a regulatory subunit for PI3Kγ | Roles in inflammation and immunity |
| PIK3CA | Encodes the catalytic subunit p110α of class IA PI3K | Oncogene frequently mutated in cancer |
| PIK3CB | Encodes p110β catalytic subunit | Involved in GPCR signaling and cancer |
| PIK3CD | Encodes p110δ catalytic subunit | Target in hematological malignancies |
| PIK3CG | Encodes p110γ catalytic subunit | Regulates immune cell function |
| PTEN | Lipid phosphatase that negatively regulates PI3K signaling | Tumor suppressor frequently lost in cancer |
| AKT1 | Serine/threonine kinase activated by PIP3 | Key downstream effector of PI3K |
| MTOR | Kinase that forms mTORC1 and mTORC2 complexes, downstream of PI3K/AKT | Central regulator of cell growth |
| IGF1 | Growth factor that activates PI3K signaling via IGF-1R | Involved in muscle hypertrophy and metabolism |
| INS | Insulin, activates PI3K via insulin receptor | Regulates glucose homeostasis |
| IRS1 | Insulin receptor substrate 1, adaptor that recruits PI3K | Mediates insulin and IGF-1 signaling |
| VPS34 (PIK3C3) | Class III PI3K, regulated by Vps15 (PIK3R4) | Controls autophagy and endosomal trafficking |
| PIK3IP1 | Negative regulator of PI3K, interacts with p110 | Potential tumor suppressor |
| INPP4B | Inositol polyphosphate 4-phosphatase, indirectly regulates PI3K signaling | Tumor suppressor in some cancers |
How Is 1-phosphatidylinositol-3-kinase regulator activity Regulated?
The activity of PI3K regulators is itself tightly regulated at multiple levels. Transcription of PIK3R1 can be influenced by insulin and other hormones. Post-translational modifications, including phosphorylation, ubiquitination, and acetylation, modulate the stability and interactions of regulatory subunits. For example, phosphorylation of p85α by Src family kinases can alter its binding to the catalytic subunit. Additionally, the availability of binding partners, such as activated RTKs or Gβγ subunits, determines whether the regulator engages with PI3K. In the context of class III PI3K, the regulatory subunit Vps15 (PIK3R4) is essential for Vps34 activity and is regulated by nutrient status. Overall, the regulation of PI3K regulators ensures that PI3K signaling is appropriately tuned to cellular needs.
1-phosphatidylinositol-3-kinase regulator activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| PIK3R1 | Cancer (glioblastoma, colorectal), insulin resistance | CRISPR knockout in cancer cell lines; knock-in of patient mutations |
| PIK3CA | Cancer (breast, colorectal, lung) | Point mutation knock-in (e.g., H1047R) in cell lines |
| PTEN | Cancer (multiple types), autism spectrum disorder | Knockout in mice and cell lines |
| PIK3C3 (VPS34) | Neurodegeneration, autophagy disorders | Knockout and point mutation models in neurons |
| PIK3R5 | Immune disorders, inflammation | Knockout in immune cells; overexpression studies |
Cancer
Dysregulation of PI3K regulator activity is a hallmark of many cancers. Mutations in PIK3R1, which encodes the p85α regulatory subunit, are found in glioblastoma, colorectal cancer, and other malignancies [1,8]. These mutations often disrupt the inhibitory interaction between p85α and the p110 catalytic subunit, leading to constitutive PI3K activation. In colorectal cancer, inorganic pyrophosphatase 1 (PPA1) has been shown to activate PI3K/Akt signaling and promote tumorigenicity and stemness. Targeting PI3K regulators is an active area of drug development.
Cardiac disease
PI3K signaling is critical for cardiac homeostasis. Reduced PI3K(p110α) activity induces atrial myopathy, and PI3K-related lipids are dysregulated in athletes with atrial fibrillation. This suggests that regulators of PI3K, which control p110α activity, play a role in atrial pathology. Experimental models with altered PI3K regulator expression could help elucidate these mechanisms.
Metabolic disorders
PI3K regulators are essential for insulin signaling and glucose uptake. Insulin-responsive transcription factors regulate the expression of genes involved in PI3K signaling. Dysregulation of this pathway contributes to insulin resistance and type 2 diabetes. Skeletal muscle atrophy following myocardial infarction involves impaired IGF-1/IGF-1R-PI3K/Akt signaling, which is modulated by PI3K regulators.
Neurological and other conditions
Class III PI3K (Vps34) and its regulator Vps15 are involved in autophagy, a process implicated in neurodegeneration. Mutations in PI3K regulatory subunits have also been linked to developmental disorders and immunodeficiency. Further research into GO:0046935 may uncover new therapeutic opportunities for these conditions.
From 1-phosphatidylinositol-3-kinase regulator activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of PIK3R1 affect PI3K signaling and cell growth? | CRISPR knockout of PIK3R1 in HEK293 or cancer cell lines |
| How do cancer-associated mutations in PIK3R1 alter PI3K activity? | Point mutation knock-in of specific PIK3R1 variants |
| Can a tagged PIK3R1 be used to study protein interactions? | Knock-in of FLAG- or GFP-tagged PIK3R1 |
| What is the effect of PIK3R1 overexpression on AKT phosphorylation? | Overexpression of PIK3R1 via lentiviral transduction |
| Which genes modulate sensitivity to PI3K inhibitors? | CRISPR library screening with a sgRNA library targeting kinases and phosphatases |
| How does PIK3R1 regulate cardiac hypertrophy in vivo? | Cardiac-specific knockout or transgenic overexpression in mice |
How to Study the 1-phosphatidylinositol-3-kinase regulator activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| CRISPR knockout | Loss of gene function | Determine if a PI3K regulator is required for signaling |
| Point mutation knock-in | Effect of specific mutations | Model cancer-associated variants |
| Overexpression | Gain of function | Assess sufficiency of a regulator to activate PI3K |
| Tagged knock-in | Protein interactions and localization | Study endogenous protein complexes |
| RNA-seq | Transcriptional changes | Identify downstream targets of PI3K regulators |
| Phospho-proteomics | Signaling pathway activation | Quantify AKT and mTOR phosphorylation |
| CRISPR library screening | Genome-wide modifiers | Discover synthetic lethal interactions |
| Bioinformatics analysis | Pathway enrichment and networks | Interpret large-scale datasets |
CRISPR-Cas9 knockout
CRISPR-Cas9 knockout is a powerful method to study the loss-of-function of PI3K regulator genes. By designing sgRNAs targeting PIK3R1 or other regulatory subunits, researchers can create isogenic cell lines to assess the impact on PI3K signaling, AKT phosphorylation, and downstream phenotypes [3,4]. This approach is widely used to validate the role of GO:0046935 in cellular processes.
Point mutation knock-in
To model disease-associated mutations in PI3K regulators, CRISPR-mediated homology-directed repair (HDR) can be used to introduce specific point mutations. For example, knock-in of PIK3R1 mutations found in cancer allows functional characterization of how these variants alter PI3K activity and cellular transformation.
Overexpression and tagged knock-in
Overexpression of wild-type or mutant PI3K regulators can be achieved via lentiviral or retroviral vectors. Alternatively, knock-in of epitope tags (e.g., FLAG, HA) at the endogenous locus enables studies of protein interactions, localization, and stability under physiological expression levels.
Library screening and bioinformatics
CRISPR library screening with sgRNA libraries targeting the kinome or specific gene families can identify modifiers of PI3K signaling. Combined with RNA-seq and bioinformatics analysis, these screens can uncover novel regulators and pathways associated with GO:0046935 [1,8].
How CRISPR Can Be Used to Study GO:0046935 1-phosphatidylinositol-3-kinase regulator activity
Knockout
CRISPR knockout of PI3K regulator genes such as PIK3R1, PIK3R2, or PIK3R3 can be achieved by delivering Cas9 and sgRNAs targeting the gene. This creates frameshift mutations and loss of protein expression. Knockout cell lines are valuable for studying the role of GO:0046935 in PI3K signaling, cell proliferation, and survival [3,4].
Point Mutation
Point mutations in PI3K regulator genes are common in cancer and other diseases. Using CRISPR-mediated HDR with a donor template, specific mutations (e.g., PIK3R1 truncating mutations) can be introduced into the endogenous locus. These models help determine whether a mutation is activating, inactivating, or neutral.
Knock-in
Knock-in of reporter tags (e.g., GFP, luciferase) or epitope tags (e.g., FLAG) into PI3K regulator genes allows real-time monitoring of expression and interaction. This is particularly useful for studying the dynamic regulation of PI3K activity in live cells.
Overexpression
Overexpression of PI3K regulators can be achieved by integrating the gene under a strong promoter using CRISPR-mediated knock-in at a safe harbor locus (e.g., AAVS1) or by lentiviral transduction. Overexpression models are used to test gain-of-function effects on PI3K signaling and cellular phenotypes.
How EDITGENE Supports 1-phosphatidylinositol-3-kinase regulator activity Research
Researchers studying 1-phosphatidylinositol-3-kinase regulator activity-related genes often need to determine whether a candidate gene is causally involved in PI3K signaling, disease pathogenesis, or drug response. EDITGENE provides a comprehensive suite of CRISPR-based services to accelerate this research, from gene knockout to precise point mutations and library screening.
Contact EDITGENE today to design your custom CRISPR model for 1-phosphatidylinositol-3-kinase regulator activity research.
Frequently Asked Questions About 1-phosphatidylinositol-3-kinase regulator activity
What is GO:0046935?
GO:0046935 is a Gene Ontology molecular function term that describes the activity of proteins that modulate the enzyme 1-phosphatidylinositol-3-kinase (PI3K). It is not the catalytic activity of PI3K itself, but the regulatory function.
What genes are involved in 1-phosphatidylinositol-3-kinase regulator activity?
Key genes include PIK3R1, PIK3R2, PIK3R3, PIK3R5, and PIK3R6, which encode regulatory subunits of PI3K. Other genes such as PIK3IP1 and PTEN also influence PI3K regulation [1,6].
How does PI3K regulator activity affect cancer?
Mutations in PI3K regulatory subunits, such as PIK3R1, can lead to constitutive activation of PI3K signaling, promoting cancer cell growth and survival. These mutations are found in glioblastoma, colorectal cancer, and other malignancies [1,8].
What diseases are associated with PI3K regulators?
PI3K regulators are implicated in cancer, cardiac disease (e.g., atrial myopathy), metabolic disorders (e.g., insulin resistance), and neurological conditions [1,3,4].
How can I study PI3K regulator activity in the lab?
Common methods include CRISPR knockout, point mutation knock-in, overexpression, and CRISPR library screening. These approaches allow functional dissection of PI3K regulators in cell lines and animal models [3,4].
What is the difference between PI3K and PI3K regulator?
PI3K is the enzyme that phosphorylates phosphatidylinositol lipids, while PI3K regulators are proteins that control the enzyme's activity, often by binding to it or modifying it.
Which CRISPR model is best for studying PI3K regulators?
The choice depends on the research question: knockout for loss-of-function, point mutation knock-in for disease variants, overexpression for gain-of-function, and tagged knock-in for interaction studies [1,3].
Can EDITGENE help with PI3K regulator research?
Yes, EDITGENE provides custom CRISPR services including knockout, point mutation, knock-in, overexpression, and library screening for PI3K regulator genes.
What is the role of PIK3R1 in PI3K signaling?
PIK3R1 encodes p85α, the regulatory subunit that stabilizes and inhibits the p110 catalytic subunit. Upon receptor activation, p85α binds to phosphotyrosine motifs and relieves inhibition, activating PI3K.
How is PI3K regulator activity regulated?
PI3K regulators are regulated by phosphorylation, ubiquitination, and protein-protein interactions. Their expression can also be controlled at the transcriptional level by insulin and other signals [1,2].
Conclusion
GO:0046935, 1-phosphatidylinositol-3-kinase regulator activity, is a critical molecular function that controls the activity of PI3K, a central enzyme in cell signaling. Dysregulation of this function is linked to cancer, cardiac disease, metabolic disorders, and other conditions. Understanding the mechanisms and genes involved in PI3K regulation is essential for developing targeted therapies. EDITGENE offers a comprehensive suite of CRISPR-based tools to study these regulators, enabling researchers to uncover new insights into PI3K biology and disease.
References
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- 2. Thiel G et al.. 2021. Insulin-Responsive Transcription Factors.. Biomolecules 11(12) PMID: 34944530
- 3. Bass-Stringer S et al.. 2025. Reduced PI3K(p110α) induces atrial myopathy, and PI3K-related lipids are dysregulated in athletes with atrial fibrillation.. J Sport Health Sci 14:101023 PMID: 39826614
- 4. Feng L et al.. 2022. Aerobic exercise and resistance exercise alleviate skeletal muscle atrophy through IGF-1/IGF-1R-PI3K/Akt pathway in mice with myocardial infarction.. Am J Physiol Cell Physiol 322(2):C164-C176 PMID: 34852207
- 5. Heden TD et al.. 2022. Regulation and role of glycophagy in skeletal muscle energy metabolism.. Autophagy 18(5):1078-1089 PMID: 34506219
- 6. Caux M et al.. 2022. Class III PI3K Biology.. Curr Top Microbiol Immunol 436:69-93 PMID: 36243840
- 8. Niu T et al.. 2023. Inorganic pyrophosphatase 1 activates the phosphatidylinositol 3-kinase/Akt signaling to promote tumorigenicity and stemness properties in colorectal cancer.. Cell Signal 108:110693 PMID: 37141926
