title: Regulation of neuronal cav3.1 channels by cyclin-dependent kinase 5 (Cdk5).
abstract: Low voltage-activated (LVA) T-type Ca2+ channels activate in response to subthreshold membrane depolarizations and therefore represent an important source of Ca2+ influx near the resting membrane potential. In neurons, these proteins significantly contribute to control relevant physiological processes including neuronal excitability, pacemaking and post-inhibitory rebound burst firing. Three subtypes of T-type channels (Cav3.1 to Cav3.3) have been identified, and using functional expression of recombinant channels diverse studies have validated the notion that T-type Ca2+ channels can be modulated by various endogenous ligands as well as by second messenger pathways. In this context, the present study reveals a previously unrecognized role for cyclin-dependent kinase 5 (Cdk5) in the regulation of native T-type channels in N1E-115 neuroblastoma cells, as well as recombinant Cav3.1channels heterologously expressed in HEK-293 cells. Cdk5 and its co-activators play critical roles in the regulation of neuronal differentiation, cortical lamination, neuronal cell migration and axon outgrowth. Our results show that overexpression of Cdk5 causes a significant increase in whole cell patch clamp currents through T-type channels in N1E-115 cells, while siRNA knockdown of Cdk5 greatly reduced these currents. Consistent with this, overexpression of Cdk5 in HEK-293 cells stably expressing Cav3.1channels upregulates macroscopic currents. Furthermore, using site-directed mutagenesis we identified a major phosphorylation site at serine 2234 within the C-terminal region of the Cav3.1subunit. These results highlight a novel role for Cdk5 in the regulation of T-type Ca2+ channels.
authors.affiliation: School of Medicine FES Iztacala, National Autonomous University of Mexico (UNAM), Tlalnepantla, Mexico.
authors.forename: Aida
authors.initials: A
authors.lastname: Calderón-Rivera
authors.affiliation: School of Medicine FES Iztacala, National Autonomous University of Mexico (UNAM), Tlalnepantla, Mexico.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Sandoval
authors.affiliation: Department of Molecular Biology and Histocompatibility, "Dr. Manuel Gea González" General Hospital, Ministry of Health, Mexico City, Mexico.
authors.forename: Ricardo
authors.initials: R
authors.lastname: González-Ramírez
authors.affiliation: Department of Biology, Faculty of Sciences, University of Chile, Santiago, Chile.
authors.forename: Christian
authors.initials: C
authors.lastname: González-Billault
authors.affiliation: Department of Cell Biology, Center for Research and Advanced Studies of the National Polytechnic Institute (Cinvestav-IPN), Mexico City, Mexico.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Felix
mesh_terms: D000818:Animals; D001369:Axons / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D020747:Calcium Channels, T-Type / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D002465:Cell Movement; D051360:Cyclin-Dependent Kinase 5 / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D016297:Mutagenesis, Site-Directed; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D010766:Phosphorylation; D012694:Serine / Q000378:metabolism*
chemical_list: C498197:Cacna1g protein, mouse; D020747:Calcium Channels, T-Type; D012694:Serine; D051360:Cyclin-Dependent Kinase 5; C495906:Cdk5 protein, mouse; D002118:Calcium