Dataset Information

Molecular characterization of the sodium channel subunits expressed in mammalian cerebellar Purkinje cells.

ABSTRACT: Inactivating and noninactivating Na+ conductances are known to generate, respectively, the rising phase and the prolonged plateau phase of cerebellar Purkinje cell (PC) action potentials. These conductances have different voltage activation levels, suggesting the possibility that two distinct types of ion channels are involved. Single Purkinje cell reverse transcription-PCR from guinea pig cerebellar slices identified two Na+ channel alpha subunit transcripts, the orthologs of RBI (rat brain I) and Nach6/Scn8a. The latter we shall name CerIII. In situ hybridization histochemistry in rat brain demonstrated broad CerIII expression at high levels in many neuronal groups in the brain and spinal cord, with little if any expression in white matter, or nerve tracts. RBII (rat brain II), the most commonly studied recombinant Na+ channel alpha subunit is not expressed in PCs. As the absence of Scn8a has been correlated with motor endplate disease (med), in which transient sodium currents are spared, RBI appears to be responsible for the transient sodium current in PC. Conversely, jolting mice with a mutated Scn8a message demonstrates PC abnormalities in rapid, simple spike generation, linking CerIII to the persistent sodium current.

SUBMITTER: Vega-Saenz de Miera EC

PROVIDER: S-EPMC21284 | biostudies-literature | 1997 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Molecular characterization of the sodium channel subunits expressed in mammalian cerebellar Purkinje cells.

Vega-Saenz de Miera E C EC Rudy B B Sugimori M M Llinás R R

Proceedings of the National Academy of Sciences of the United States of America 19970601 13

Inactivating and noninactivating Na+ conductances are known to generate, respectively, the rising phase and the prolonged plateau phase of cerebellar Purkinje cell (PC) action potentials. These conductances have different voltage activation levels, suggesting the possibility that two distinct types of ion channels are involved. Single Purkinje cell reverse transcription-PCR from guinea pig cerebellar slices identified two Na+ channel alpha subunit transcripts, the orthologs of RBI (rat brain I) ...[more]

PMID: 9192691

Similar Datasets

Project description:Background:Voltage-gated sodium (NaV) channels are heteromeric proteins consisting of a single pore forming ?-subunit associated with one or two auxiliary ?-subunits. These channels are classically known for being responsible of action potential generation and propagation in excitable cells; but lately they have been reported as widely expressed and regulated in several human cancer types. We have previously demonstrated the overexpression of NaV1.6 channel in cervical cancer (CeCa) biopsies and primary cultures, and its contribution to cell migration and invasiveness. Here, we investigated the expression of NaV channels ?-subunits (NaV?s) in the CeCa cell lines HeLa, SiHa and CaSki, and determined their contribution to cell proliferation, migration and invasiveness. Methods:We assessed the expression of NaV?s in CeCa cell lines by performing RT-PCR and western blotting experiments. We also evaluated CeCa cell lines proliferation, migration, and invasion by in vitro assays, both in basal conditions and after inducing changes in NaV?s levels by transfecting specific cDNAs or siRNAs. The potential role of NaV?s in modulating the expression of NaV ?-subunits in the plasma membrane of CeCa cells was examined by the patch-clamp whole-cell technique. Furthermore, we investigated the role of NaV?1 on cell cycle in SiHa cells by flow cytometry. Results:We found that the four NaV?s are expressed in the three CeCa cell lines, even in the absence of functional NaV ?-subunit expression in the plasma membrane. Functional in vitro assays showed differential roles for NaV?1 and NaV?4, the latter as a cell invasiveness repressor and the former as a migration abolisher in CeCa cells. In silico analysis of NaV?4 expression in cervical tissues corroborated the downregulation of this protein expression in CeCa vs normal cervix, supporting the evidence of NaV?4's role as a cell invasiveness repressor. Conclusions:Our results contribute to the recent conception about NaV?s as multifunctional proteins involved in cell processes like ion channel regulation, cell adhesion and motility, and even in metastatic cell behaviors. These non-canonical functions of NaV?s are independent of the presence of functional NaV ?-subunits in the plasma membrane and might represent a new therapeutic target for the treatment of cervical cancer.

Dataset Information

Molecular characterization of the sodium channel subunits expressed in mammalian cerebellar Purkinje cells.

Publications

Molecular characterization of the sodium channel subunits expressed in mammalian cerebellar Purkinje cells.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets