PROTEIN HALF-LIVES OF CALMODULIN AND THE PLASMA-MEMBRANE CA-ATPASE INRAT-BRAIN

We report the half-lives for two proteins involved in the regulation o f intracellular calcium in the brain: the plasma membrane Ca-ATPase an d its regulatory protein, calmodulin. [C-14]-labeled leucine was injec ted into seven month old adult Fischer 344 rats and the time-dependent appearance and loss of radioactivity was monitored in both the serum and proteins from the brains of rats sacrificed from 4 hours to 13 day s after injection, Experimental data obtained for calmodulin and the p lasma membrane Ca-ATPase are best described by theoretical curves acco unting for leucine reutilization that assume apparent half-lives of 18 (+/-2) hours and 12 (+/-1) days, respectively. (C) 1997 Academic Pres s.