title: The RNA-binding protein SERBP1 interacts selectively with the signaling protein RACK1.
abstract: The RACK1 protein interacts with numerous proteins involved in signal transduction, the cytoskeleton, and mRNA splicing and translation. We used the 2-hybrid system to identify additional proteins interacting with RACK1 and isolated the RNA-binding protein SERBP1. SERPB1 shares amino acid sequence homology with HABP4 (also known as Ki-1/57), a component of the RNA spicing machinery that has been shown previously to interact with RACK1. Several different isoforms of SERBP1, generated by alternative mRNA splicing, interacted with RACK1 with indistinguishable interaction strength, as determined by a 2-hybrid beta-galactosidase assay. Analysis of deletion constructs of SERBP1 showed that the C-terminal third of the SERBP1 protein, which contains one of its two substrate sites for protein arginine N-methyltransferase 1 (PRMT1), is necessary and sufficient for it to interact with RACK1. Analysis of single amino acid substitutions in RACK1, identified in a reverse 2-hybrid screen, showed very substantial overlap with those implicated in the interaction of RACK1 with the cAMP-selective phosphodiesterase PDE4D5. These data are consistent with SERBP1 interacting selectively with RACK1, mediated by an extensive interaction surface on both proteins.
authors.affiliation: Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294-3300, USA; Department of Pharmacology, University of Alabama at Birmingham, Birmingham, AL 35294-3300, USA. Electronic address: graemebolger@BIpharmacorp.com.
authors.forename: Graeme B
authors.initials: GB
authors.lastname: Bolger
mesh_terms: D019943:Amino Acid Substitution; D001665:Binding Sites; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4 / Q000235:genetics / Q000378:metabolism; D006801:Humans; D011485:Protein Binding; D060066:Protein Interaction Maps / Q000235:genetics*; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D011484:Protein-Arginine N-Methyltransferases / Q000235:genetics* / Q000378:metabolism; D012326:RNA Splicing / Q000235:genetics; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D000075370:Receptors for Activated C Kinase / Q000235:genetics* / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D013379:Substrate Specificity
chemical_list: D020033:Protein Isoforms; D016601:RNA-Binding Proteins; D000075370:Receptors for Activated C Kinase; D012097:Repressor Proteins; C428129:SERBP1 protein, human; C099988:PRMT1 protein, human; D011484:Protein-Arginine N-Methyltransferases; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4; C517376:PDE4D protein, human
keywords: 2-Hybrid; HABP4; PDE4; PDE4D5; RACK1; SERBP1