PI3 Kinase p85α Antibody [L7D21]

Application: Reactivity: Mouse, Rat, Human, African green monkey

Usage Information

Dilution
WB1:1000 IP1:50 IF1:250 FCM1:150

Application
WB, IP, IF, FCM

Reactivity
Mouse, Rat, Human, African green monkey

Source
Rabbit Monoclonal Antibody

Storage Buffer
PBS, pH 7.2+50% Glycerol+0.05% BSA+0.01% NaN3

Storage (from the date of receipt)
-20°C (avoid freeze-thaw cycles), 2 years

Predicted MW Observed MW
83 kDa, 41 kDa 46-90 kDa
^*Why do the predicted and actual molecular weights differ? The following reasons may explain differences between the predicted and actual protein molecular weight.

Positive Control	Human fetal liver; Human fetal heart; Human fetal kidney; Mouse brain; Mouse heart; Rat brain; Rat heart; Rat kidney; HepG2 cells; MCF7 cells; Raji cells; NIH/3T3 cells; C6 cells; RAW 264.7 cells; PC-12 cells
Negative Control

Datasheet & SDS

Biological Description

Specificity
PI3 Kinase p85α Antibody [L7D21] detects endogenous levels of total PI3 Kinase p85α protein.

Clone
L7D21

Synonym(s)
GRB1; PIK3R1; PI3K regulatory subunit alpha; PtdIns-3-kinase regulatory subunit alpha; PtdIns-3-kinase regulatory subunit p85-alpha

Background
PI3 Kinase p85α (PIK3R1) is the principal regulatory subunit (~85 kDa) of class IA phosphoinositide 3-kinases (PI3K), partnering with catalytic p110 subunits (such as p110α) to relay signals from receptor tyrosine kinases (RTKs) like the insulin receptor and EGFR. It is ubiquitously expressed and plays a central role in regulating cell growth, metabolism, and survival. p85α contains an N-terminal SH3 domain, two proline-rich regions (PR1/PR2), a RhoGAP/BH domain, and two SH2 domains (nSH2 and cSH2) that flank an inter-SH2 (iSH2) helical region responsible for binding and inhibiting p110. Key regulatory motifs include Tyr607-609 and phosphorylation sites at Ser361 and Ser652, which modulate its function. p85α can also form homodimers through SH3:PR and BH:BH domain interactions when not complexed with p110. The primary role of p85α is to relieve autoinhibition of p110 upon phosphotyrosine (pTyr) binding to its SH2 domains, such as those on IRS-1, recruiting the PI3K complex to the plasma membrane. Here, PI3K generates PIP3, leading to activation of the AKT/mTORC1 pathway, which controls glucose uptake, protein synthesis, proliferation, and anti-apoptotic responses. Free p85α homodimers, in contrast, stabilize PTEN and help restrain excessive PI3K signaling. p85α sets the sensitivity of PI3K responses by competing with p110 complexes at low stimulus levels, orchestrates insulin signaling via IRS docking, and supports cytokinesis through lipid-independent mechanisms. Mutations in PIK3R1, such as gain-of-function changes that enhance p110 activity or loss-of-function mutations that weaken PTEN stabilization, are found in 5–10% of cancers and can drive tumorigenesis, as well as contribute to insulin resistance and type 2 diabetes via impaired AKT signaling.

Background

PI3 Kinase p85α (PIK3R1) is the principal regulatory subunit (~85 kDa) of class IA phosphoinositide 3-kinases (PI3K), partnering with catalytic p110 subunits (such as p110α) to relay signals from receptor tyrosine kinases (RTKs) like the insulin receptor and EGFR. It is ubiquitously expressed and plays a central role in regulating cell growth, metabolism, and survival. p85α contains an N-terminal SH3 domain, two proline-rich regions (PR1/PR2), a RhoGAP/BH domain, and two SH2 domains (nSH2 and cSH2) that flank an inter-SH2 (iSH2) helical region responsible for binding and inhibiting p110. Key regulatory motifs include Tyr607-609 and phosphorylation sites at Ser361 and Ser652, which modulate its function. p85α can also form homodimers through SH3:PR and BH:BH domain interactions when not complexed with p110. The primary role of p85α is to relieve autoinhibition of p110 upon phosphotyrosine (pTyr) binding to its SH2 domains, such as those on IRS-1, recruiting the PI3K complex to the plasma membrane. Here, PI3K generates PIP3, leading to activation of the AKT/mTORC1 pathway, which controls glucose uptake, protein synthesis, proliferation, and anti-apoptotic responses. Free p85α homodimers, in contrast, stabilize PTEN and help restrain excessive PI3K signaling. p85α sets the sensitivity of PI3K responses by competing with p110 complexes at low stimulus levels, orchestrates insulin signaling via IRS docking, and supports cytokinesis through lipid-independent mechanisms. Mutations in PIK3R1, such as gain-of-function changes that enhance p110 activity or loss-of-function mutations that weaken PTEN stabilization, are found in 5–10% of cancers and can drive tumorigenesis, as well as contribute to insulin resistance and type 2 diabetes via impaired AKT signaling.

References
https://pubmed.ncbi.nlm.nih.gov/38317714/ https://pubmed.ncbi.nlm.nih.gov/21478295/

Reference Table for Selecting PVDF Membrane Pore Size Specifications

Protein Size (kDa)	PVDF Transfer Membrane Pore Size (μm)
< 10	0.22
10-20	0.22
20-30	0.45
30-45	0.45
45-70	0.45
80-100	0.45
100-140	0.45
> 140	0.45

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Protein Size (kDa)	Separating Gel Percentage
4-40	20%
12-45	15%
10-70	12.5%
15-100	10%
25-100	8%
60-210	5%