Inhibition of neurite extension by overexpression of individual domains of LIM kinase 1.
Lin-11, Isl-1 and Mec-3 (LIM) kinases are serine/threonine kinases that phosphorylate cofilin, an actin depolymerizing protein. LIM kinases have a highly modular structure composed of two N-terminal LIM domains (LIM 1/2), a PSD-95, Dlg and ZO-1 (PDZ) domain and a C-terminal protein kinase domain. Here, we overexpressed individual domains of mouse LIM kinase 1 (LIMK1) in PC12 cells and investigated their effects on neurite outgrowth. Although none of the LIMK1 domains had an effect on spontaneous neurite outgrowth, the N-terminal LIM 1/2 domains strongly inhibited differentiation of PC12 cells after stimulation with both nerve growth factor (NGF) and the Rho-kinase inhibitor Y-27632. In contrast, the overexpressed PDZ domain reduced neurite outgrowth only when differentiation had been induced by Y-27632, but not by NGF. Our data suggest that the different non-catalytic N-terminal domains of LIMK1 contribute to the regulation of neurite extension by using distinct signal transduction pathways.
Birkenfeld
J
J
Department of Neurochemistry, Max-Planck-Institute for Brain Research, Frankfurt, Germany.
Betz
H
H
Roth
D
D
D000577:Amides / Q000494:pharmacology; D000818:Animals; D002460:Cell Line; D048429:Cell Size; D004791:Enzyme Inhibitors / Q000494:pharmacology; D017930:Genes, Reporter; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D054461:Lim Kinases; D051379:Mice; D020932:Nerve Growth Factor / Q000494:pharmacology; D016501:Neurites / Q000187:drug effects / Q000378:metabolism*; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020798:Two-Hybrid System Techniques
D000577:Amides; D004791:Enzyme Inhibitors; D011725:Pyridines; D011993:Recombinant Fusion Proteins; C108830:Y 27632; D020932:Nerve Growth Factor; D011494:Protein Kinases; C515892:LIMK1 protein, human; D054461:Lim Kinases; C515893:Limk1 protein, mouse; C515894:Limk1 protein, rat