Phosphatidylinositol 3-kinase regulatory subunit alpha is an enzyme that in humans is encoded by the PIK3R1 gene.[5]
Phosphatidylinositol 3-kinase phosphorylates the inositol ring of phosphatidylinositol at the 3-prime position. The enzyme comprises a 110 kD catalytic subunit and a regulatory subunit of either 85, 55, or 50 kD. The Pik3r1 gene locus encodes the 85 kD regulatory subunit, as well as 55 and 50 kD regulatory subunits. It used to be thought that alternative splicing of this gene resulted in three transcript variants encoding different isoforms.[6] In fact, it has since been shown that the 55 and 50kD subunits have their own promotors within the gene locus Pik3r1.[7]
Phosphatidylinositol 3-kinase plays an important role in the metabolic actions of insulin, and a mutation in this gene has been associated with insulin resistance.[8] Suppression specifically of the 85kD subunit in early murine embryoid body development results in a transient cell-cell adhesion deficiency, mediated by transient downregulation of the adhesion molecule integrin-beta1 (ITGB1).[7]
Mutations in PIK3R1 are implicated in cases of breast cancer.[9]
Mutations in PIK3R1 are associated to SHORT syndrome.[10]
PIK3R1 has been shown to interact with:
PDB gallery
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1bfi: SOLUTION STRUCTURE OF THE C-TERMINAL SH2 DOMAIN OF THE P85ALPHA REGULATORY SUBUNIT OF PHOSPHOINOSITIDE 3-KINASE, NMR, 30 STRUCTURES
1bfj: SOLUTION STRUCTURE OF THE C-TERMINAL SH2 DOMAIN OF THE P85ALPHA REGULATORY SUBUNIT OF PHOSPHOINOSITIDE 3-KINASE, NMR, MINIMIZED AVERAGE STRUCTURE
1fu5: NMR STRUCTURE OF THE N-SH2 DOMAIN OF THE P85 SUBUNIT OF PI3-KINASE COMPLEXED TO A DOUBLY PHOSPHORYLATED PEPTIDE DERIVED FROM POLYOMAVIRUS MIDDLE T ANTIGEN
1fu6: NMR STRUCTURE OF THE N-SH2 DOMAIN OF THE P85 SUBUNIT OF PI3-KINASE
1h9o: PHOSPHATIDYLINOSITOL 3-KINASE, P85-ALPHA SUBUNIT: C-TERMINAL SH2 DOMAIN COMPLEXED WITH A TYR751 PHOSPHOPEPTIDE FROM THE PDGF RECEPTOR, CRYSTAL STRUCTURE AT 1.79 A
1oo3: P395S mutant of the p85 regulatory subunit of the N-terminal src homology 2 domain of PI3-Kinase
1oo4: P395S mutant of the p85 regulatory subunit of the N-terminal src homology 2 domain of PI3-Kinase complexed to a peptide derived from PDGFr
1pbw: STRUCTURE OF BCR-HOMOLOGY (BH) DOMAIN
1pht: PHOSPHATIDYLINOSITOL 3-KINASE P85-ALPHA SUBUNIT SH3 DOMAIN, RESIDUES 1-85
1pic: PHOSPHATIDYLINOSITOL 3-KINASE, P85-ALPHA SUBUNIT: C-TERMINAL SH2 DOMAIN COMPLEXED WITH A TYR751 PHOSPHOPEPTIDE FROM THE PDGF RECEPTOR, NMR, MINIMIZED MEAN STRUCTURE
1pks: STRUCTURE OF THE PI3K SH3 DOMAIN AND ANALYSIS OF THE SH3 FAMILY
1pkt: STRUCTURE OF THE PI3K SH3 DOMAIN AND ANALYSIS OF THE SH3 FAMILY
1pnj: SOLUTION STRUCTURE AND LIGAND-BINDING SITE OF THE SH3 DOMAIN OF THE P85ALPHA SUBUNIT OF PHOSPHATIDYLINOSITOL 3-KINASE
1qad: Crystal Structure of the C-Terminal SH2 Domain of the P85 alpha Regulatory Subunit of Phosphoinositide 3-Kinase: An SH2 domain mimicking its own substrate
2iug: CRYSTAL STRUCTURE OF THE PI3-KINASE P85 N-TERMINAL SH2 DOMAIN
2iuh: CRYSTAL STRUCTURE OF THE PI3-KINASE P85 N-TERMINAL SH2 DOMAIN IN COMPLEX WITH C-KIT PHOSPHOTYROSYL PEPTIDE
2iui: CRYSTAL STRUCTURE OF THE PI3-KINASE P85 N-TERMINAL SH2 DOMAIN IN COMPLEX WITH PDGFR PHOSPHOTYROSYL PEPTIDE
2pna: STRUCTURE OF AN SH2 DOMAIN OF THE P85 ALPHA SUBUNIT OF PHOSPHATIDYLINOSITOL-3-OH KINASE
2pnb: STRUCTURE OF AN SH2 DOMAIN OF THE P85 ALPHA SUBUNIT OF PHOSPHATIDYLINOSITOL-3-OH KINASE
2pni: SOLUTION STRUCTURE AND LIGAND-BINDING SITE OF THE SH3 DOMAIN OF THE P85ALPHA SUBUNIT OF PHOSPHATIDYLINOSITOL 3-KINASE
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