Homeostatic tuning of Ca2+ signal transduction by members of the calpacitin protein family

✍ Scribed by Dan Gerendasy

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 424 KB
• Volume: 58
• Category: Article
• ISSN: 0360-4012
• DOI: 10.1002/(sici)1097-4547(19991001)58:1<107::aid-jnr11>3.0.co;2-g

✦ Synopsis

The calpacitin protein family is made up of small, abundantly expressed proteins that bind to the Ca 2؉free form of calmodulin (CaM) with an affinity equal to or greater than that of the Ca 2؉ -containing form. Their CaM-binding domains are homologous and contain an IQ motif. Two members of this family, growth-associated protein-43 (GAP-43) and RC3, have been implicated in long-term potentiation (LTP) and the elaboration of pre-and postsynaptic structures. Computer-aided modeling of calpacitin-CaM interactions suggests that these molecules regulate Ca 2؉ flux size and CaM availability. Simulation of the interactions between the calpacitins CaM and Ca 2؉ imply that GAP-43 and RC3 tune and homeostatically constrain the Ca 2؉ signal transduction system. In so doing, they link Ca 2؉ fluxes to downstream elements of a signaling cascade that generates LTP.