Biophysical Journal 72: 1287-1294 (1997)
© 1997 the Biophysical Society

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Heubach, J F Articles by Chalovich, J M Search for Related Content PubMed PubMed Citation Articles by Heubach, J F Articles by Chalovich, J M

Inhibition of cross-bridge binding to actin by caldesmon fragments in skinned skeletal muscle fibers.

Institute of Naturheilkunde, University Clinics Ulm, Germany.

ABSTRACT

Several regions within the 35-kDa COOH-terminal portion of caldesmon have been implicated in the ability of caldesmon to inhibit actin-activated myosin ATPase activity. To further define the functional regions of caldesmon, we have studied the effects of three chymotryptic fragments, one fragment produced by CNBr digestion and two fragments produced by digestion with submaxillaris arginase C protease, on the relaxed stiffness and active force of rabbit psoas fibers. Each of the regions of caldesmon studied had either direct or indirect effects on single-fiber mechanics. The 35-kDa and 20-kDa fragments of caldesmon, like intact caldesmon, were effective inhibitors of fiber stiffness, a measure of cross-bridge attachment. The 7.3-kDa and 10-kDa fragments, which constitute the NH2 and COOH halves of the 20-kDa fragment, inhibited both relaxed fiber stiffness and active force production, but with a reduced efficacy compared to the 20-kDa fragment. These results suggest that several regions within the 35-kDa COOH-terminal region of caldesmon are required for optimum function of caldesmon and that function includes inhibition of weak cross-bridge attachment and force production.

This article has been cited by other articles:

				S. M. Roth, R. E. Ferrell, D. G. Peters, E. J. Metter, B. F. Hurley, and M. A. Rogers Influence of age, sex, and strength training on human muscle gene expression determined by microarray Physiol Genomics, September 3, 2002; 10(3): 181 - 190. [Abstract] [Full Text] [PDF]