p160 RhoA-binding kinase ROKalpha induces neurite retraction.
We previously reported that the activation of prostaglandin E receptor EP3 subtype caused neurite retraction via small GTPase Rho in the EP3B receptor-expressing PC12 cells (Katoh, H., Negishi, M., and Ichikawa, A. (1996) J. Biol. Chem. 271, 29780-29784). However, a potential downstream effector of Rho that induces neurite retraction was not identified. Here we examined the morphological effect of p160 RhoA-binding kinase ROKalpha, a target for RhoA recently identified, on the nerve growth factor-differentiated PC12 cells. Microinjection of the catalytic domain of ROKalpha rapidly induced neurite retraction similar to that induced by microinjection of a constitutively active Rho, RhoV14, whereas microinjection of the kinase-deficient catalytic domain of ROKalpha did not induce neurite retraction. This morphological change was observed even though C3 exoenzyme, which was known to inactivate Rho, had been preinjected. On the other hand, microinjection of the Rho-binding domain or the pleckstrin homology domain of ROKalpha inhibited the EP3 receptor-induced neurite retraction. These results demonstrate that ROKalpha induces neurite retraction acting downstream of Rho in neuronal cells.
Katoh
H
H
Department of Physiological Chemistry, Faculty of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606, Japan.
Aoki
J
J
Ichikawa
A
A
Negishi
M
M
D000818:Animals; D002454:Cell Differentiation; D002465:Cell Movement; D004789:Enzyme Activation; D047908:Intracellular Signaling Peptides and Proteins; D008845:Microinjections; D009414:Nerve Growth Factors / Q000494:pharmacology; D016501:Neurites / Q000187:drug effects / Q000502:physiology*; D016716:PC12 Cells / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D051381:Rats; D018078:Receptors, Prostaglandin E / Q000378:metabolism; D058308:Receptors, Prostaglandin E, EP3 Subtype; D011994:Recombinant Proteins / Q000494:pharmacology; D015398:Signal Transduction; D054460:rho-Associated Kinases
D047908:Intracellular Signaling Peptides and Proteins; D009414:Nerve Growth Factors; D018078:Receptors, Prostaglandin E; D058308:Receptors, Prostaglandin E, EP3 Subtype; D011994:Recombinant Proteins; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases