Dynamic association of the Ca2+ channel alpha1A subunit and SNAP-25 in round or neurite-emitting chromaffin cells
| Autor: | Carmen Montiel, Luisa M. Solís-Garrido, Eva Andres-Mateos, Rocío Serantes, Antonio G. García, Jesús Cruces, Jaime Renart, Ana M. de Lucas-Cerrillo, Marcos Aldea |
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| Rok vydání: | 2005 |
| Předmět: |
Models
Molecular Neurite Synaptosomal-Associated Protein 25 Protein subunit Chromaffin Cells Phosphatidylethanolamine N-Methyltransferase Blotting Western Fluorescent Antibody Technique Dopamine beta-Hydroxylase Biology Mice Calcium Channels N-Type Neurites Animals Humans Immunoprecipitation RNA Messenger Cells Cultured Microscopy Confocal Base Sequence Dose-Response Relationship Drug Reverse Transcriptase Polymerase Chain Reaction General Neuroscience Snap Cell Differentiation Blotting Northern Calcium Channel Blockers Rats Protein Subunits Gene Expression Regulation Potassium Ca2 channels Calcium Cattle Rabbits Humanities Sequence Alignment |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| ISSN: | 0953-816X |
| Popis: | Although the specific interaction between synaptic protein SNAP-25 and the α1A subunit of the Cav2.1 channels, which conduct P/Q-type Ca2+ currents, has been confirmed in in vitro-translated proteins and brain membrane studies, the question of how native proteins can establish this association in situ in developing neurons remains to be elucidated. Here we report data regarding this interaction in bovine chromaffin cells natively expressing both proteins. The two carboxyl-terminal splice variants of the α1A subunit identified in these cells share a synaptic protein interaction ('synprint') site within the II/III loop segment and are immunodetected by a specific antibody against bovine α1A protein. Moreover, both α1A isoforms form part of the P/Q-channels-SNARE complexes in situ because they are coimmunoprecipitated from solubilized chromaffin cell membranes by a monoclonal SNAP-25 antibody. The distribution of α1A and SNAP-25 was studied in round or transdifferentiated chromaffin cells using confocal microscopy and specific antibodies: the two proteins are colocalized at the cell body membrane in both natural cell types. However, during the first stages of the cell transdifferentiation process, SNAP-25 migrates alone out to the developing growth cone and what will become the nerve endings and varicosities of the mature neurites; α1A follows and colocalizes to SNAP-25 in the now mature processes. These observations lead us to propose that the association between SNAP-25 and M1A during neuritogenesis might promote not only the efficient coupling of the exocytotic machinery but also the correct insertion of P/Q-type channels at specialized active zones in presynaptic neuronal terminals. © Federation of European Neuroscience Societies. This work was supported by a grant to C.M. from Ministerio de Ciencia y Tecnología, Spain (SAF2002-0151). E.A.M. is a Fellow of the Universidad Autónoma de Madrid; L.M.S.G. and A.M.L.C. are Fellows of Ministerio de Educación y Ciencia, Spain; R.S. is a Fellow of FIS, Instituto de Salud Carlos III, Ministerio de Sanidad y Consumo, Spain. |
| Databáze: | OpenAIRE |
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