Cargando…

Biochemical properties and subcellular distribution of the BI and rbA isoforms of alpha 1A subunits of brain calcium channels

Biochemical properties and subcellular distribution of the class A calcium channel alpha 1 subunits (alpha 1A) from rat and rabbit brain were examined using site-directed anti-peptide antibodies specific for rat rbA (anti-CNA3) and for rabbit BI (anti-NBI-1 and anti-NBI-2) isoforms of alpha 1A. In i...

Descripción completa

Detalles Bibliográficos
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1996
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2120867/
https://www.ncbi.nlm.nih.gov/pubmed/8707834
_version_ 1782141596248047616
collection PubMed
description Biochemical properties and subcellular distribution of the class A calcium channel alpha 1 subunits (alpha 1A) from rat and rabbit brain were examined using site-directed anti-peptide antibodies specific for rat rbA (anti-CNA3) and for rabbit BI (anti-NBI-1 and anti-NBI-2) isoforms of alpha 1A. In immunoblotting experiments, anti-CNA3 specifically identifies multiple alpha 1A polypeptides with apparent molecular masses of 210, 190, and 160 kD, and anti-NBI-1 and anti-NBI-2 specifically recognize 190-kD alpha 1A polypeptides in rat brain membrane. In rabbit brain, anti-NBI-1 or anti-NBI-2 specifically detect alpha 1A polypeptides with apparent molecular masses of 220, 200, and 190 kD, while anti-CNA3 specifically recognizes 190-kD alpha 1A polypeptides. These polypeptides evidently represent multiple isoforms of alpha 1A present in both rat and rabbit brain. Anti-CNA3 specifically immunoprecipitates high affinity receptor sites for omega- conotoxin MVIIC (Kd approximately 100 pM), whereas anti-NBI-2 immunoprecipitates two distinct affinity receptor sites for omega- conotoxin MVIIC (Kd approximately 100 pM and approximately 1 microM). Coimmunoprecipitation experiments indicate that alpha 1A subunits recognized by anti-CNA3 and anti-NBI-2 are associated with syntaxin in a stable, SDS-resistant complex and with synaptotagmin. Immunofluorescence studies reveal that calcium channels recognized by anti-NBI-2 are localized predominantly in dendrites and nerve terminals forming synapses on them, while calcium channels recognized by anti- CNA3 are localized more prominently in cell bodies and in nerve terminals. The mossy fiber terminals in hippocampus and the terminals of climbing and parallel fibers in cerebellum are differentially stained by these isoform-specific antibodies. These results indicate that both rbA and BI isoforms of alpha 1A are expressed in rat and rabbit brain and form calcium channels having alpha 1A subunits with distinct molecular mass, pharmacology, and subcellular localization.
format Text
id pubmed-2120867
institution National Center for Biotechnology Information
language English
publishDate 1996
publisher The Rockefeller University Press
record_format MEDLINE/PubMed
spelling pubmed-21208672008-05-01 Biochemical properties and subcellular distribution of the BI and rbA isoforms of alpha 1A subunits of brain calcium channels J Cell Biol Articles Biochemical properties and subcellular distribution of the class A calcium channel alpha 1 subunits (alpha 1A) from rat and rabbit brain were examined using site-directed anti-peptide antibodies specific for rat rbA (anti-CNA3) and for rabbit BI (anti-NBI-1 and anti-NBI-2) isoforms of alpha 1A. In immunoblotting experiments, anti-CNA3 specifically identifies multiple alpha 1A polypeptides with apparent molecular masses of 210, 190, and 160 kD, and anti-NBI-1 and anti-NBI-2 specifically recognize 190-kD alpha 1A polypeptides in rat brain membrane. In rabbit brain, anti-NBI-1 or anti-NBI-2 specifically detect alpha 1A polypeptides with apparent molecular masses of 220, 200, and 190 kD, while anti-CNA3 specifically recognizes 190-kD alpha 1A polypeptides. These polypeptides evidently represent multiple isoforms of alpha 1A present in both rat and rabbit brain. Anti-CNA3 specifically immunoprecipitates high affinity receptor sites for omega- conotoxin MVIIC (Kd approximately 100 pM), whereas anti-NBI-2 immunoprecipitates two distinct affinity receptor sites for omega- conotoxin MVIIC (Kd approximately 100 pM and approximately 1 microM). Coimmunoprecipitation experiments indicate that alpha 1A subunits recognized by anti-CNA3 and anti-NBI-2 are associated with syntaxin in a stable, SDS-resistant complex and with synaptotagmin. Immunofluorescence studies reveal that calcium channels recognized by anti-NBI-2 are localized predominantly in dendrites and nerve terminals forming synapses on them, while calcium channels recognized by anti- CNA3 are localized more prominently in cell bodies and in nerve terminals. The mossy fiber terminals in hippocampus and the terminals of climbing and parallel fibers in cerebellum are differentially stained by these isoform-specific antibodies. These results indicate that both rbA and BI isoforms of alpha 1A are expressed in rat and rabbit brain and form calcium channels having alpha 1A subunits with distinct molecular mass, pharmacology, and subcellular localization. The Rockefeller University Press 1996-07-02 /pmc/articles/PMC2120867/ /pubmed/8707834 Text en This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Articles
Biochemical properties and subcellular distribution of the BI and rbA isoforms of alpha 1A subunits of brain calcium channels
title Biochemical properties and subcellular distribution of the BI and rbA isoforms of alpha 1A subunits of brain calcium channels
title_full Biochemical properties and subcellular distribution of the BI and rbA isoforms of alpha 1A subunits of brain calcium channels
title_fullStr Biochemical properties and subcellular distribution of the BI and rbA isoforms of alpha 1A subunits of brain calcium channels
title_full_unstemmed Biochemical properties and subcellular distribution of the BI and rbA isoforms of alpha 1A subunits of brain calcium channels
title_short Biochemical properties and subcellular distribution of the BI and rbA isoforms of alpha 1A subunits of brain calcium channels
title_sort biochemical properties and subcellular distribution of the bi and rba isoforms of alpha 1a subunits of brain calcium channels
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2120867/
https://www.ncbi.nlm.nih.gov/pubmed/8707834