The multidomain protein Trio binds the LAR transmembrane tyrosine phosphatase, contains a protein kinase domain, and has separate rac-specific and rho-specific guanine nucleotide exchange factor domains

摘要

rho-like GTP binding proteins play an essen- tial role in regulating cell growth and actin polymerization. These molecular switches are positively regulated by guanine nucleotide exchange factors (GEFs) that promote the ex- change of GDP for GTP. Using the interaction-trap assay to identify candidate proteins that bind the cytoplasmic region of the LAR transmembrane protein tyrosine phosphatase (PT- Pase), we isolated a cDNA encoding a 2861-amino acid protein termed Trio that contains three enzyme domains: two funct- ional GEF domains and a protein serine/threonine kinase (PSK) domain.