Connexin hemichannel composition determines the FGF-1-induced membrane permeability and free [Ca2+](i) responses

Schalper, KA; Palacios-Prado, N; Retamal, MA.; Shoji, KF; Martínez AD; Sáez JC

Abstract

Cell surface hemichannels (HCs) composed of different connexin (Cx) types are present in diverse cells and their possible role on FGF-1-induced cellular responses remains unknown. Here, we show that FGF-1 transiently (4-14 h, maximal at 7 h) increases the membrane permeability through HCs in HeLa cells expressing Cx43 or Cx45 under physiological extracellular Ca2+/ Mg2+ concentrations. The effect does not occur in HeLa cells expressing HCs constituted of Cx26 or Cx43 with its C-terminus truncated at aa 257, or in parental nontransfected HeLa cells. The increase in membrane permeability is associated with a rise in HC levels at the cell surface and a proportional increase in HC unitary events. The response requires an early intracellular free Ca2+ concentration increase, activation of a p38 MAP kinase-dependent pathway, and a regulatory site of Cx subunit C-terminus. The FGF-1-induced rise in membrane permeability is also associated with a late increase in intracellular free Ca2+ concentration, suggesting that responsive HCs allow Ca2+ influx. The cell density of Cx26 and Cx43 HeLa transfectants cultured in serum-free medium was differentially affected by FGF-1. Thus, the FGF-1-induced cell permeabilization and derived consequences depend on the Cx composition of HCs. © 2008 by The American Society for Cell Biology.

Más información

Título según WOS: Connexin hemichannel composition determines the FGF-1-induced membrane permeability and free [Ca2+](i) responses
Título según SCOPUS: Connexin hemichannel composition determines the FGF-1-induced membrane permeability and free [Ca2+]i responses
Título de la Revista: MOLECULAR BIOLOGY OF THE CELL
Volumen: 19
Número: 8
Editorial: AMER SOC CELL BIOLOGY
Fecha de publicación: 2008
Página de inicio: 3501
Página final: 3513
Idioma: English
URL: http://www.molbiolcell.org/cgi/doi/10.1091/mbc.E07-12-1240
DOI:

10.1091/mbc.E07-12-1240

Notas: ISI, SCOPUS