Phosphatidylinositol 3-kinase regulatory subunit alpha - P26450 (P85A_MOUSE)

 

Protein Feature View of PDB entries mapped to a UniProtKB sequence  

 
Function
Binds to activated (phosphorylated) protein-Tyr kinases, through its SH2 domain, and acts as an adapter, mediating the association of the p110 catalytic unit to the plasma membrane. Necessary for the insulin-stimulated increase in glucose uptake and glycogen synthesis in insulin-sensitive tissues. Plays an important role in signaling in response to FGFR1, FGFR2, FGFR3, FGFR4, KITLG/SCF, KIT, PDGFRA and PDGFRB. Likewise, plays a role in ITGB2 signaling (By similarity). Modulates the cellular response to ER stress by promoting nuclear translocation of XBP1 isoform 2 in a ER stress- and/or insulin-dependent manner during metabolic overloading in the liver and hence plays a role in glucose tolerance improvement (PubMed:20348926). UniProt
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Subunit Structure
Heterodimer of a regulatory subunit PIK3R1 and a p110 catalytic subunit (PIK3CA, PIK3CB or PIK3CD). Interacts (via SH2 domains) with CCDC88A/GIV (tyrosine-phosphorylated form); the interaction enables recruitment of PIK3R1 to the EGFR receptor, enhancing PI3K activity and cell migration (By similarity). Interacts with XBP1 isoform 2; the interaction is direct and induces translocation of XBP1 isoform 2 into the nucleus in a ER stress- and/or insulin-dependent but PI3K-independent manner (PubMed:20348926). Interacts with PIK3R2; the interaction is dissociated in an insulin-dependent manner (PubMed:20348926). Interacts with phosphorylated LAT, LAX1 and TRAT1 upon TCR activation. The SH2 domains interact with the YTHM motif of phosphorylated INSR in vitro. Also interacts with tyrosine-phosphorylated IGF1R in vitro. Interacts with IRS1 and phosphorylated IRS4. Interacts with NISCH and RUFY3 (By similarity). Interacts with phosphorylated TOM1L1. Interacts with phosphorylated LIME1 upon TCR or BCR activation. Interacts with CBLB. Interacts with CD28 and CD3Z upon T-cell activation. Interacts with SOCS7 and HCST. Interacts with AXL, FASLG, FGR, HCK, KIT and BCR. Interacts with PTK2/FAK1 (By similarity). Interacts with PDGFRB (tyrosine phosphorylated) (By similarity). Interacts with NTRK1 (phosphorylated upon ligand-binding) (By similarity). Interacts (via SH2 domain) with CSF1R (tyrosine phosphorylated) (PubMed:9312046). Interacts with FER. Interacts with FGFR1, FGFR2, FGFR3 and FGFR4 (phosphorylated) (Probable). Interacts with PDGFRA (tyrosine phosphorylated). Interacts with LYN (via SH3 domain); this enhances enzyme activity. Interacts with ERBB4. Interacts (via SH2 domain) with TEK/TIE2 (tyrosine phosphorylated). Interacts with FAM83B; activates the PI3K/AKT signaling cascade (By similarity). Interacts with APPL1 and APPL2 (PubMed:25328665). Interacts with SRC (By similarity). Interacts with ALOX5; this interaction bridges ALOX5 with CD40 after CD40 ligation in B cells and leads to the production of reactive oxygen species (ROS) (By similarity). UniProt
Domain
The SH3 domain mediates the binding to CBLB. UniProt
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Data origin/color codes
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Data in green originates from UniProtKB  
Variation data (sourced from UniProt) shows non-genetic variation from the ExPASy   and dbSNP   websites.
Data in yellow originates from Pfam  , by interacting with the HMMER3 web site  
Data in purple originates from Phosphosite  .
Data in orange originates from the SCOP   (version 1.75) and SCOPe   (version 2.04) classifications.
Data in grey has been calculated using BioJava  . Protein disorder predictions are based on JRONN (Troshin, P. and Barton, G. J. unpublished), a Java implementation of RONN  
  • Red: potentially disorderd region
  • Blue: probably ordered region.
Hydropathy has been calculated using a sliding window of 15 residues and summing up scores from standard hydrophobicity tables.
  • Red: hydrophobic
  • Blue: hydrophilic.
Data in lilac represent the genomic exon structure projected onto the UniProt sequence.
Data in blue originates from PDB
  • Secstruc: Secondary structure projected from representative PDB entries onto the UniProt sequence.
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Validation Track

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Data in red indicates combined ranges of Homology Models from the SWISS-MODEL Repository  
The PDB to UniProt mapping is based on the data provided by the EBI SIFTS project. See also Velankar et al., Nucleic Acids Research 33, D262-265 (2005).
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