ErbB3 is involved in activation of phosphatidylinositol 3-kinase by epidermal growth factor.

摘要: Abstract Conflicting results concerning the ability of epidermal growth factor (EGF) receptor to associate with and/or activate phosphatidylinositol (PtdIns) 3-kinase have been published. Despite EGF stimulate production PtdIns products and cause appearance activity in antiphosphotyrosine immunoprecipitates several cell lines, we did not detect EGF-stimulated anti-EGF immunoprecipitates. This result is consistent lack a phosphorylated Tyr-X-X-Met motif, p85 Src homology 2 (SH2) domain recognition sequence, this sequence. The homolog, ErbB2 protein, also lacks motif. However, ErbB3 protein has seven repeats motif carboxy-terminal unique domain. Here show that A431 cells, which express both ErbB3, coprecipitates (p180erbB3) response EGF. p180erbB3 shown be tyrosine In contrast, different mechanism for activation occurs certain cells (PC12 A549 cells). Thus, first time can mediate responses expressing receptor.