title: Distinct roles for the two Rho GDP/GTP exchange factor domains of kalirin in regulation of neurite growth and neuronal morphology.
abstract: The actin cytoskeleton, essential for neuronal development, is regulated in part by small GTP binding proteins of the Rho subfamily. Kalirin-9, with two Rho subfamily-specific GDP/GTP exchange factor (GEF) domains, localizes to neurites and growth cones of primary cortical neurons. Kalirin-9 overexpression in cultured cortical neurons induces longer neurites and altered neuronal morphology. Expression of the first GEF domain alone results in drastically shortened axons and excessive growth cones, mediated by Rac1. Expression of the second GEF domain alone induces axonal over-elongation and abundant filopodial neurites, mediated by RhoA. Coordination of the actions of the individual GEF domains through their presence in Kalirin-9, with its Sec14p, spectrin, and Src homology domain 3 motifs, is essential for regulating neurite extension and neuronal morphology.
authors.affiliation: Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
authors.forename: P
authors.initials: P
authors.lastname: Penzes
authors.forename: R C
authors.initials: RC
authors.lastname: Johnson
authors.forename: V
authors.initials: V
authors.lastname: Kambampati
authors.forename: R E
authors.initials: RE
authors.lastname: Mains
authors.forename: B A
authors.initials: BA
authors.lastname: Eipper
mesh_terms: D016475:3T3 Cells; D000818:Animals; D002352:Carrier Proteins; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D020439:Growth Cones / Q000187:drug effects / Q000502:physiology; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism*; D008563:Membrane Lipids / Q000378:metabolism; D051379:Mice; D016501:Neurites / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000494:pharmacology; D013049:Spectrin / Q000378:metabolism; D014162:Transfection; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism; D020830:rac1 GTP-Binding Protein / Q000378:metabolism; D020741:rho GTP-Binding Proteins / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D020662:Guanine Nucleotide Exchange Factors; C102365:Kalrn protein, rat; D008563:Membrane Lipids; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; D013049:Spectrin; D020764:cdc42 GTP-Binding Protein; D020830:rac1 GTP-Binding Protein; D020741:rho GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein