Cell Biology

Caveolae Conducting Calcium

Science's STKE  12 Nov 2002:
Vol. 2002, Issue 158, pp. tw414
DOI: 10.1126/stke.2002.158.tw414

Caveolae are specialized membrane domains that function in endocytosis and contain relatively high concentrations of signaling molecules. Isshiki et al. now present evidence that caveolae serve as preferential sites of Ca2+ influx across the plasma membrane when intracellular stores of Ca2+ are depleted. The authors fused the calcium sensor yellow chameleon 3.1 to the COOH-terminal end of caveolin-1 to target the sensor to caveolae. Then, they compared Ca2+ signals at the caveolae to those from unmodified yellow chameleon in the cytoplasm or from another fusion protein that targeted the sensor to the plasma membrane. When Ca2+ was depleted from the endoplasmic reticulum of fetal bovine endothelial cells by exposure of the cells to adenosine triphosphate (ATP) and thapsigargin, Ca2+ entry into the cells occurred preferentially at caveolae, apparently through store-operated channels of the TRP (transient receptor potential) family. The authors propose that caveolae may function as preassembled, compartmentalized signaling units that can be recruited when needed by exocytosis and fusion with the plasma membrane

M. Isshiki, Y. Ying, T. Fujita, R. G. W. Anderson, A molecular sensor detects signal transduction from caveolae in living cells. J. Biol. Chem. 277, 43389-43398 (2002). [Abstract] [Full Text]