p80 ROKalpha binding protein is a novel splice variant of CRMP-1 which associates with CRMP-2 and modulates RhoA-induced neuronal morphology.
Using antibody against the Rho binding domain of ROKalpha, two neuronal phosphoproteins of 62 and 80 kDa were co-immunoprecipitated from brain extracts. Peptide analysis revealed their identity as collapsin response mediator proteins (CRMPs); p62 was CRMP-2 whereas p80 was a novel splice form of CRMP-1 with an extended N-terminus. p80 CRMP-1 was able to complex with CRMP-2, suggesting that p80 CRMP-1 and CRMP-2 form oligomers. CRMP-2 was the major substrate of ROK. p80 CRMP-1 interacted with the kinase domain of ROKalpha, resulting in inhibition of the catalytic activity towards other substrates. Over-expression of p80 CRMP-1 and CRMP-2 together counteracted the effects of RhoA on neurite retraction, an effect enhanced by mutation of the ROK phosphorylation site in CRMP-2. p80 CRMP-1 and CRMP-2 may be modulators of RhoA-dependent signaling, through interaction with and regulation of ROKalpha.
Leung
Thomas
T
Glaxo-IMCB Group, Institute of Molecular and Cell Biology, 30 Medical Drive, 117609, Singapore. mcbthoml@imcb.nus.edu.sg
Ng
Yvonne
Y
Cheong
Albert
A
Ng
Chong Han
CH
Tan
Ivan
I
Hall
Christine
C
Lim
Louis
L
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism; D019556:COS Cells; D002384:Catalysis; D002874:Chromosome Mapping; D018076:DNA, Complementary / Q000378:metabolism; D019281:Dimerization; D005822:Genetic Vectors; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D016716:PC12 Cells; D010455:Peptides; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D011233:Precipitin Tests; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism* / Q000502:physiology*; D017434:Protein Structure, Tertiary; D051381:Rats; D015398:Signal Transduction; D014162:Transfection; D014407:Tumor Cells, Cultured; D054460:rho-Associated Kinases; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*; D000098855:Collapsin Response Mediator Protein 1
D018076:DNA, Complementary; D036341:Intercellular Signaling Peptides and Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins; D010455:Peptides; D010750:Phosphoproteins; D000098855:Collapsin Response Mediator Protein 1; C095114:collapsin response mediator protein-2; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D020742:rhoA GTP-Binding Protein