INVESTIGADORES
REY Osvaldo
artículos
Título:
"Intracellular Ca2+ oscillations generated via the extracellular Ca2+-sensing receptor (CaSR) in response to extracellular Ca2+ or l-phenylalanine: Impact of the highly conservative mutation Ser170Thr
Autor/es:
STEVEN H YOUNG, O. REY. E. ROZENGURT
Revista:
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
Editorial:
ACADEMIC PRESS INC ELSEVIER SCIENCE
Referencias:
Lugar: Amsterdam; Año: 2015 vol. 467 p. 1 - 6
ISSN:
0006-291X
Resumen:
The extracellular Ca(2+)-sensing receptor (CaSR) is an allosteric protein that responds to changes in the extracellular concentration of Ca(2+) ([Ca(2+)]e) and aromatic amino acids with the production of different patterns of oscillations in intracellular Ca(2+) concentration ([Ca(2+)]i). An increase in [Ca(2+)]e stimulates sinusoidal oscillations in [Ca(2+)]i whereas aromatic amino acid-induced CaR activation in the presence of a threshold [Ca(2+)]e promotes transient oscillations in [Ca(2+)]i. Here, we examined spontaneous and ligand-evoked [Ca(2+)]i oscillations in single HEK-293 cells transfected with the wild type CaSR or with a mutant CaSR in which Ser170 was converted to Thr (CaSRS170T). Our analysis demonstrates that cells expressing CaSRS170T display [Ca(2+)]i oscillations in the presence of low concentrations of extracellular Ca(2+) and respond to L-Phe with robust transient [Ca(2+)]i oscillations. Our results indicate that the S170T mutation induces a marked increase in CaSR sensitivity to [Ca(2+)]e and imply that the allosteric regulation of the CaSR by aromatic amino acids is not only mediated by an heterotropic positive effect on Ca(2+) binding cooperativity but, as biased agonists, aromatic amino acids stabilize a CaSR conformation that couples to a different signaling pathway leading to transient [Ca(2+)]i oscillations.