Collapsin response mediator protein switches RhoA and Rac1 morphology in N1E-115 neuroblastoma cells and is regulated by Rho kinase.
The formation and directional guidance of neurites involves dynamic regulation of Rho family GTPases. Rac and Cdc42 promote neurite outgrowth, whereas Rho activation causes neurite retraction. Here we describe a role for collapsin response mediator protein (Crmp-2), a neuronal protein implicated in axonal outgrowth and a component of the semaphorin 3A pathway, in switching GTPase signaling when expressed in combination with either dominant active Rac or Rho. In neuroblastoma N1E-115 cells, co-expression of Crmp-2 with dominant active RhoA V14 induced Rac morphology, cell spreading and ruffling (and the formation of neurites). Conversely, co-expression of Crmp-2 with dominant active Rac1 V12 inhibited Rac morphology, and in cells already expressing Rac1 V12, Crmp-2 caused localized peripheral collapse, involving Rho (and Cdc42) activation. Rho kinase was a pivotal regulator of Crmp-2; Crmp-2 phosphorylation was required for Crmp-2/Rac1 V12 inhibition, but not Crmp-2/RhoA V14 induction, of Rac morphology. Thus Crmp-2, regulated by Rho kinase, promotes outgrowth and collapse in response to active Rho and Rac, respectively, reversing their usual morphological effects and providing a mechanism for dynamic modulation of growth cone guidance.
Hall
C
C
Department of Neurochemistry, Institute of Neurology, University College London, 1 Wakefield Street, London WC1N IPJ, United Kingdom. C.Hall@ion.ucl.ac.uk
Brown
M
M
Jacobs
T
T
Ferrari
G
G
Cann
N
N
Teo
M
M
Monfries
C
C
Lim
L
L
D016475:3T3 Cells; D000818:Animals; D001921:Brain / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D005799:Genes, Dominant; D006023:Glycoproteins / Q000378:metabolism; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D016297:Mutagenesis, Site-Directed; D009419:Nerve Tissue Proteins / Q000378:metabolism* / Q000502:physiology*; D010766:Phosphorylation; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D051381:Rats; D040121:Semaphorin-3A; D015398:Signal Transduction; D014162:Transfection; D014407:Tumor Cells, Cultured; D020830:rac1 GTP-Binding Protein / Q000378:metabolism*; D054460:rho-Associated Kinases; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
D018076:DNA, Complementary; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins; D040121:Semaphorin-3A; C095114:collapsin response mediator protein-2; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D020830:rac1 GTP-Binding Protein; D020742:rhoA GTP-Binding Protein