title: Dimerization is required for SH3PX1 tyrosine phosphorylation in response to epidermal growth factor signalling and interaction with ACK2.
abstract: SH3PX1 [SNX9 (sorting nexin 9)] is a member of SNX super-family that is recognized by sharing a PX (phox homology) domain. We have previously shown that SH3PX1, phosphorylated by ACK2 (activated Cdc42-associated tyrosine kinase 2), regulates the degradation of EGF (epidermal growth factor) receptor. In mapping the tyrosine phosphorylation region, we found that the C-terminus of SH3PX1 is required for its tyrosine phosphorylation. Further analysis indicates that this region, known as the coiled-coil domain or the BAR (Bin-amphiphysin-Rvs homology) domain, is the dimerization domain of SH3PX1. Truncation of as little as 13 amino acid residues at the very C-terminus in the coiled-coil/BAR domain of SH3PX1 resulted in no dimerization, no ACK2-catalysed and EGF-stimulated tyrosine phosphorylation and no interaction with ACK2. The intracellular localization of SH3PX1 became dysfunctional upon truncation in the BAR domain. Taken together, our results indicate that the dimerization, which is mediated by the BAR domain, is essential for the intracellular function of SH3PX1.
authors.affiliation: Weis Center for Research, Geisinger Clinic, 100 N. Academy Avenue, Danville, PA 17822, USA.
authors.forename: Chandra
authors.initials: C
authors.lastname: Childress
authors.forename: Qiong
authors.initials: Q
authors.lastname: Lin
authors.forename: Wannian
authors.initials: W
authors.lastname: Yang
mesh_terms: D000818:Animals; D019556:COS Cells; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002522:Chlorocebus aethiops; D019281:Dimerization; D004815:Epidermal Growth Factor / Q000378:metabolism*; D006801:Humans; D009154:Mutation; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D015398:Signal Transduction; D058305:Sorting Nexins; D033921:Vesicular Transport Proteins
chemical_list: D002352:Carrier Proteins; C400533:SNX9 protein, human; D058305:Sorting Nexins; D033921:Vesicular Transport Proteins; D019000:Phosphotyrosine; D004815:Epidermal Growth Factor; D011505:Protein-Tyrosine Kinases