Increased calmodulin in cultured skin fibroblasts from patients with cystic fibrosis

Abstract

We have found that the content of an endogenous calcium-binding protein, calmodulin, is greater in cystic fibrosis fibroblasts than in normal cells. Homogenate preparations from CF fibroblasts contained 2.4 ± 0.2 ng calmodulin/μg protein while normal fibroblasts contained 1.5 ± 0.1 ng calmodulin/μg protein. Cyclic AMP phosphodiesterase activity, however, was the same in cystic fibrosis and normal fibroblasts. The increased calmodulin in cystic fibrosis cells could be involved in the changes in calcium metabolism and cyclic AMP production found in these cells.