INVESTIGADORES
BOLLO Mariana Ines
artículos
Título:
A novel lipid binding protein is a factor required for MgATP stimulation of the squid nerve Na(+)/Ca(2+) exchanger
Autor/es:
BERBERIÁN G, BOLLO M, MONTICH G, ROBERTS G, DEGIORGIS JA, DIPOLO R, BEAUGÉ L
Revista:
BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES
Editorial:
Elsevier
Referencias:
Lugar: Amsterdam; Año: 2008 vol. 1788 p. 1255 - 1262
ISSN:
0005-2736
Resumen:
Here we identify a cytosolic factor essential for MgATP up-regulation of the squid nerve Na(+)/Ca(2+) exchanger. Mass spectroscopy and Western blot analysis established that this factor is a member of the lipocalin super family of lipid binding proteins of 132 amino acids in length. We named it Regulatory protein of the squid nerve sodium calcium exchanger (ReP1-NCXSQ). ReP-1-NCXSQ was cloned, over expressed and purified. Far-UV circular dichroism and infrared spectra suggest a majority of beta-strand in the secondary structure. Moreover, the predicted tertiary structure indicates ten beta-sheets and two short alpha-helices characteristic of most lipid binding proteins. Functional experiments showed that in order to be active ReP1-NCXSQ must become phosphorylated in the presence of MgATP by a kinase that is Staurosporin insensitive. Even more, the phosphorylated ReP1-NCXSQ is able to stimulate the exchanger in the absence of ATP. In addition to the identification of a new member of the lipid binding protein family, this work shows, for the first time, the requirement of a lipid binding protein for metabolic regulation of an ion transporting system