Summary: A Cluster of Basic Repeats in the Dystrophin Rod Domain
Binds F-actin through an Electrostatic Interaction*
(Received for publication, June 22, 1998, and in revised form, August 7, 1998)
Kurt J. Amann, Brian A. Renley§, and James M. Ervasti§¶
From the Graduate Program in Cellular and Molecular Biology and the §Department of Physiology,
University of Wisconsin Medical School, Madison, Wisconsin 53706
The dystrophin rod domain is composed of 24 spec-
trin-like repeats and was thought to act mainly as a
flexible spacer between the amino-terminal actin bind-
ing domain and carboxyl-terminal membrane-associ-
ated domains. We previously demonstrated that a frag-
ment of the dystrophin rod domain also binds F-actin.
However, the nature and extent of rod domain associa-
tion with F-actin is presently unclear. To begin address-
ing these questions, we characterized two recombinant
proteins representing adjacent regions of the dystro-
phin rod. DYS1416 (amino acids 1416­1880) bound F-
actin with a Kd of 14.2 5.2 M and a stoichiometry of 1
mol:mol of actin. However, DYS1030 (amino acids 1030­
1494) failed to bind F-actin, suggesting that not all rod

Source: Amann, Kurt - Molecular and Cellular Pharmacology Training Program & Department of Zoology, University of Wisconsin at Madison

Collections: Biology and Medicine