title: Preferential targeting of p39-activated Cdk5 to Rac1-induced lamellipodia.
abstract: Cdk5 is a member of the cyclin-dependent kinase (Cdk) family that plays a role in various neuronal activities including brain development, synaptic regulation, and neurodegeneration. Cdk5 requires the neuronal specific activators, p35 and p39 for subcellular compartmentalization. However, it is not known how active Cdk5 is recruited to F-actin cytoskeleton, which is a Cdk5 target. Here we found p35 and p39 localized to F-actin rich regions of the plasma membrane and investigated the underlying targeting mechanism in vitro by expressing them with Rho family GTPases in Neuro2A cells. Both p35 and p39 accumulated at the cell peripheral lamellipodia and perinuclear regions, where active Rac1 is localized. Interestingly, p35 and p39 displayed different localization patterns as p35 was found more at the perinuclear region and p39 was found more in peripheral lamellipodia. We then confirmed this distinct localization in primary hippocampal neurons. We also determined that the localization of p39 to lamellipodia requires myristoylation and Lys clusters within the N-terminal p10 region. Additionally, we found that p39-Cdk5, but not p35-Cdk5 suppressed lamellipodia formation by reducing Rac1 activity. These results suggest that p39-Cdk5 has a dominant role in Rac1-dependent lamellipodial activity.
authors.affiliation: Laboratory of Molecular Neuroscience, Department of Biological Sciences, Tokyo Metropolitan University, Minami-osawa, Hachioji, Tokyo 192-0397, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Ito
authors.affiliation: Laboratory of Molecular Neuroscience, Department of Biological Sciences, Tokyo Metropolitan University, Minami-osawa, Hachioji, Tokyo 192-0397, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Asada
authors.affiliation: Laboratory of Molecular Neuroscience, Department of Biological Sciences, Tokyo Metropolitan University, Minami-osawa, Hachioji, Tokyo 192-0397, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kobayashi
authors.affiliation: Laboratory of Molecular Neuroscience, Department of Biological Sciences, Tokyo Metropolitan University, Minami-osawa, Hachioji, Tokyo 192-0397, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Takano
authors.affiliation: Laboratory of Molecular Neuroscience, Department of Biological Sciences, Tokyo Metropolitan University, Minami-osawa, Hachioji, Tokyo 192-0397, Japan.
authors.forename: Govinda
authors.initials: G
authors.lastname: Sharma
authors.affiliation: Laboratory of Molecular Neuroscience, Department of Biological Sciences, Tokyo Metropolitan University, Minami-osawa, Hachioji, Tokyo 192-0397, Japan.
authors.forename: Taro
authors.initials: T
authors.lastname: Saito
authors.affiliation: Division of Cell Biology, Department of Biosciences, School of Science, Kitasato University, 1-15-1 Kitasato, Minami, Sagamihara 252-0373, Japan.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Ohta
authors.affiliation: Department of Cell Pharmacology, Graduate School of Medicine, Nagoya University, 65 Tsurumai, Showa, Nagoya 466-8550, Japan.
authors.forename: Mutsuki
authors.initials: M
authors.lastname: Amano
authors.affiliation: Department of Cell Pharmacology, Graduate School of Medicine, Nagoya University, 65 Tsurumai, Showa, Nagoya 466-8550, Japan.
authors.forename: Kozo
authors.initials: K
authors.lastname: Kaibuchi
authors.affiliation: Laboratory of Molecular Neuroscience, Department of Biological Sciences, Tokyo Metropolitan University, Minami-osawa, Hachioji, Tokyo 192-0397, Japan. Electronic address: hisanaga-shinichi@tmu.ac.jp.
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Hisanaga
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D002478:Cells, Cultured; D051360:Cyclin-Dependent Kinase 5 / Q000378:metabolism; D004622:Embryo, Mammalian; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D020439:Growth Cones / Q000378:metabolism; D006624:Hippocampus / Q000166:cytology; D047468:Immunoprecipitation; D051379:Mice; D009154:Mutation / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009447:Neuroblastoma / Q000473:pathology; D009474:Neurons / Q000166:cytology; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism; D011554:Pseudopodia / Q000378:metabolism*; D051381:Rats; D014162:Transfection; D020741:rho GTP-Binding Proteins / Q000378:metabolism*
chemical_list: D000199:Actins; C108298:Cdk5 activator p39; C489428:Myc protein, mouse; D009419:Nerve Tissue Proteins; D016271:Proto-Oncogene Proteins c-myc; C491771:Rnd1 protein, rat; D049452:Green Fluorescent Proteins; D051360:Cyclin-Dependent Kinase 5; D020741:rho GTP-Binding Proteins
keywords: Cdk5; Cell adhesion; Cyclin-dependent kinase; Lamellipodia; Rac1; Rho small GTPase