CALCIUM CHANNELS Current Trends in Calcium Currents

Abstract:

Identification and characterization of new calcium channels that may function to control calcium-dependent signaling continues at a rapid pace. Sano et al. (see the Perspective by Levitan and Cibulsky) describe the human LTRP2 channel, a member of the transient receptor potential (TRP) family (see Review by Montell) that is abundantly expressed in the blood. The channel contains a motif in its cytoplasmic tail that is associated with nucleotide hydrolase activity. In cells transfected with LTRP2, conductance of the channel was directly activated by ADPR (adenosine diphosphate ribose), or ß-NAD (ß-nicotinamide adenine dinucleotide). In immunocyte cell lines, they observed a similar inward calcium current when cells were exposed to ADPR or ß-NAD. In a Perspecitve, Levitan and Cibulsky summarize other recent work that has characterizing a different TRP-family member and in which different regulatory properties and ADPR pyrophosphatase activity are ascribed to LTRP2.

Y. Sano, K. Inamura, A. Miyake, S. Mochizuki, H. Yokoi, H. Matsushime, K. Furuichi, Immunocyte Ca²⁺ influx system mediated by LTRPC2. Science 293, 1327-1330 (2001). [Abstract] [Full Text]

I. B. Levitan, S. M. Cibulsky, TRP ion channels--Two proteins in one. Science 293, 1270-1271 (2001). [Full Text]

C. Montell, Physiology, phylogeny, and functions of the TRP superfamily of cation channels. Science's STKE (2001), http://stke.sciencemag.org/cgi/content/full/OC_sigtrans;2001/90/re1. [Full Text]