title: POSH2 is a RING finger E3 ligase with Rac1 binding activity through a partial CRIB domain.
abstract: The Plenty of SH3 domains protein (POSH) is an E3 ligase and a scaffold in the JNK mediated apoptosis, linking Rac1 to downstream components. We here describe POSH2 which was identified from a p21-activated kinase 2 (PAK2) interactor screen. POSH2 is highly homologous with other members of the POSH family; it contains four Src homology 3 (SH3) domains and a RING finger domain which confers E3 ligase activity to the protein. In addition POSH2 contains an N-terminal extension which is conserved among its mammalian counterparts. POSH2 interacts with GTP-loaded Rac1. We have mapped this interaction to a previously unrecognized partial Cdc42/Rac1-interactive binding domain.
authors.affiliation: Institute of Medical Technology, University of Tampere, Tampere, Finland.
authors.forename: Satu
authors.initials: S
authors.lastname: Kärkkäinen
authors.forename: Maarten
authors.initials: M
authors.lastname: van der Linden
authors.forename: G Herma
authors.initials: GH
authors.lastname: Renkema
mesh_terms: D000595:Amino Acid Sequence; D006801:Humans; D008969:Molecular Sequence Data; D054829:RING Finger Domains; D044767:Ubiquitin-Protein Ligases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism; D020830:rac1 GTP-Binding Protein / Q000378:metabolism*
chemical_list: C552957:SH3RF3 protein, human; D044767:Ubiquitin-Protein Ligases; D020764:cdc42 GTP-Binding Protein; D020830:rac1 GTP-Binding Protein