Cloning of human p55 γ, a regulatory subunit of phosphatidylinositol 3-kinase, by a yeast two-hybrid library screen with the insulin-like growth factor-I receptor
We have used the yeast two-hybrid system to identify proteins that interact with the intracellular domain of the insulin-like growth factor-I receptor (IGFIR). In a search of a human fetal brain library we identified a cDNA encoding a protein that is the human homologue of mouse p55 PIK, a regulator...
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Published in | Gene Vol. 209; no. 1; pp. 175 - 183 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Netherlands
Elsevier B.V
16.03.1998
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Subjects | |
Online Access | Get full text |
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Summary: | We have used the yeast two-hybrid system to identify proteins that interact with the intracellular domain of the insulin-like growth factor-I receptor (IGFIR). In a search of a human fetal brain library we identified a cDNA encoding a protein that is the human homologue of mouse p55
PIK, a regulatory subunit of phosphatidylinositol 3-kinase (hp55
γ). The hp55
γ protein interacts strongly with the activated IGFIR but not with the kinase-negative mutant receptor. hp55
γ also interacts with the insulin receptor (IR) in the yeast two-hybrid system. The putative hp55
γ protein is composed of a unique amino terminal region followed by a proline-rich motif and two Src homology 2 (SH2) domains, which are highly homologous to those in mouse p55
PIK, rat p55
γ, human p85
α and bovine p85
β; it contains no SH3 domain. hp55
γ mRNAs are expressed in most human fetal and adult tissues with particularly high abundance in adult testis. Splice variant(s) of hp55
γ, one of which has a deletion of 36
amino acids at the amino terminus and another which has an insertion of 59
amino acids at position 256 between the SH2 domains, were also identified. A GST–hp55
γ fusion protein interacts in vitro with both the activated IGFIR and IR derived from mammalian cells. Our findings suggest that hp55
γ interacts with the IGFIR and IR and may be involved in PI 3-kinase activation by these receptors. |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2 |
ISSN: | 0378-1119 1879-0038 |
DOI: | 10.1016/S0378-1119(98)00045-6 |