title: TMEM16A alternative splicing isoforms in Xenopus tropicalis: distribution and functional properties.
abstract: Oocytes of Xenopus tropicalis elicit a Ca(2+)-dependent outwardly rectifying, low-activating current (ICl,Ca) that is inhibited by Cl(-) channel blockers. When inactivated, ICl,Ca shows an exponentially decaying tail current that is related to currents generated by TMEM16A ion channels. Accordingly, RT-PCR revealed the expression of five alternatively spliced isoforms of TMEM16A in oocytes, which, after expression in HEK-293 cells, gave rise to fully functional Cl(-) channels. Upon hyperpolarization to -80 mV a transient current was observed only in isoforms that carry the exon 1d, coding for two potentially phosphorylatable Threonine residues. The identified isoforms are differentially expressed in several tissues of the frog. Thus, it appears that X. tropicalis oocytes express TMEM16A that gives rise to a Ca(2+)-dependent Cl(-) current, which is different from the previously reported voltage-dependent outwardly rectifying Cl(-) current.
authors.affiliation: Departamento de Neurobiología Celular y Molecular, Laboratorio de Neurobiología Molecular y Celular, Instituto de Neurobiología, Campus UNAM Juriquilla, Querétaro, Qro CP 76230, Mexico.
authors.forename: A
authors.initials: A
authors.lastname: Huanosta-Gutiérrez
authors.affiliation: Departamento de Neurobiología Celular y Molecular, Laboratorio de Neurobiología Molecular y Celular, Instituto de Neurobiología, Campus UNAM Juriquilla, Querétaro, Qro CP 76230, Mexico.
authors.forename: A E
authors.initials: AE
authors.lastname: Espino-Saldaña
authors.affiliation: Departamento de Neurobiología Celular y Molecular, Laboratorio de Neurobiología Molecular y Celular, Instituto de Neurobiología, Campus UNAM Juriquilla, Querétaro, Qro CP 76230, Mexico.
authors.forename: J P
authors.initials: JP
authors.lastname: Reyes
authors.affiliation: Departamento de Neurobiología Celular y Molecular, Laboratorio de Neurobiología Molecular y Celular, Instituto de Neurobiología, Campus UNAM Juriquilla, Querétaro, Qro CP 76230, Mexico.
authors.forename: A
authors.initials: A
authors.lastname: Pétriz
authors.affiliation: Departamento de Neurobiología Celular y Molecular, Laboratorio de Neurobiología Molecular y Celular, Instituto de Neurobiología, Campus UNAM Juriquilla, Querétaro, Qro CP 76230, Mexico.
authors.forename: R
authors.initials: R
authors.lastname: Miledi
authors.affiliation: Departamento de Neurobiología Celular y Molecular, Laboratorio de Neurobiología Molecular y Celular, Instituto de Neurobiología, Campus UNAM Juriquilla, Querétaro, Qro CP 76230, Mexico. Electronic address: ataulfo@unam.mx.
authors.forename: A
authors.initials: A
authors.lastname: Martínez-Torres
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D002118:Calcium / Q000378:metabolism; D018118:Chloride Channels / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism; D003001:Cloning, Molecular; D015870:Gene Expression; D057809:HEK293 Cells; D006801:Humans; D009865:Oocytes / Q000378:metabolism; D020033:Protein Isoforms / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D014981:Xenopus / Q000235:genetics* / Q000378:metabolism; D029867:Xenopus Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism
chemical_list: D018118:Chloride Channels; D002712:Chlorides; D020033:Protein Isoforms; D029867:Xenopus Proteins; C559904:xANO2 protein, Xenopus; D002118:Calcium
keywords: Anoctamin 1; Calcium-activated chloride channels; Splice isoforms