Biomaterial Database

Regulation of the p85/p110alpha phosphatidylinositol 3'-kinase. Distinct roles for the n-terminal and c-terminal SH2 domains. 1998

J Yu, and C Wjasow, and J M Backer

Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.

Our previous studies on the p85/p110alpha phosphatidylinositol 3-kinase showed that the p85 regulatory subunit inhibits the p110alpha catalytic subunit, and that phosphopeptide activation of p85/p110alpha dimers reflects a disinhibition of p110alpha (Yu, J., Zhang, Y., McIlroy, J., Rordorf-Nikolic, T., Orr, G. A., and Backer, J. M. (1998) Mol. Cell. Biol. 18, 1379-1387). We now define the domains of p85 required for inhibition of p110alpha. The iSH2 domain of p85 is sufficient to bind p110alpha but does not inhibit it. Inhibition of p110alpha requires the presence of the nSH2 domain linked to the iSH2 domain. Phosphopeptides increase the activity of nSH2/iSH2-p110alpha dimers, demonstrating that the nSH2 domain mediates both inhibition of p110alpha and disinhibition by phosphopeptides. In contrast, phosphopeptides did not increase the activity of iSH2/cSH2-p110alpha dimers, or dimers composed of p110alpha and an nSH2/iSH2/cSH2 construct containing a mutant nSH2 domain. Phosphopeptide binding to the cSH2 domain increased p110alpha activity only in the context of an intact p85 containing both the nSH2 domain and residues 1-322 (the SH3, proline-rich and breakpoint cluster region-homolgy domains). These data suggest that the nSH2 domain of p85 is a direct regulator of p110alpha activity. Regulation of p110alpha by phosphopeptide binding to the cSH2 domain occurs by a mechanism that requires the additional presence of the nSH2 domain and residues 1-322 of p85.

UI	MeSH Term	Description	Entries
D010748	Phosphopeptides	PEPTIDES that incorporate a phosphate group via PHOSPHORYLATION.	Phosphopeptide
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D002460	Cell Line	Established cell cultures that have the potential to propagate indefinitely.	Cell Lines,Line, Cell,Lines, Cell
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013329	Structure-Activity Relationship	The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.	Relationship, Structure-Activity,Relationships, Structure-Activity,Structure Activity Relationship,Structure-Activity Relationships
D016296	Mutagenesis	Process of generating a genetic MUTATION. It may occur spontaneously or be induced by MUTAGENS.	Mutageneses
D018411	Spodoptera	A genus of owlet moths of the family Noctuidae. These insects are used in molecular biology studies during all stages of their life cycle.	Spodoptera frugiperda,Spodoptera frugiperdas,Spodopteras,frugiperdas, Spodoptera
D018909	src Homology Domains	Regions of AMINO ACID SEQUENCE similarity in the SRC-FAMILY TYROSINE KINASES that fold into specific functional tertiary structures. The SH1 domain is a CATALYTIC DOMAIN. SH2 and SH3 domains are protein interaction domains. SH2 usually binds PHOSPHOTYROSINE-containing proteins and SH3 interacts with CYTOSKELETAL PROTEINS.	SH Domains,SH1 Domain,SH2 Domain,SH3 Domain,src Homology Region 2 Domain,Homology Domain, src,Homology Domains, src,SH Domain,SH1 Domains,SH2 Domains,SH3 Domains,src Homology Domain
D019281	Dimerization	The process by which two molecules of the same chemical composition form a condensation product or polymer.	Dimerizations
D019869	Phosphatidylinositol 3-Kinases	Phosphotransferases that catalyzes the conversion of 1-phosphatidylinositol to 1-phosphatidylinositol 3-phosphate. Many members of this enzyme class are involved in RECEPTOR MEDIATED SIGNAL TRANSDUCTION and regulation of vesicular transport with the cell. Phosphatidylinositol 3-Kinases have been classified both according to their substrate specificity and their mode of action within the cell.	PI-3 Kinase,Phosphatidylinositol-3-OH Kinase,PtdIns 3-Kinase,PI 3-Kinase,PI-3K,PI3 Kinases,PI3-Kinase,Phosphoinositide 3 Kinases,Phosphoinositide 3-Hydroxykinase,PtdIns 3-Kinases,3-Hydroxykinase, Phosphoinositide,Kinase, PI-3,Kinase, Phosphatidylinositol-3-OH,Kinases, PI3,Kinases, Phosphoinositide 3,PI 3 Kinase,PI3 Kinase,Phosphatidylinositol 3 Kinases,Phosphatidylinositol 3 OH Kinase,Phosphoinositide 3 Hydroxykinase,PtdIns 3 Kinase,PtdIns 3 Kinases