PMID: 24239457

Authors:

Fuson K, Rice A, Mahling R, Snow A, Nayak K, Shanbhogue P, Meyer AG, Redpath GM, Hinderliter A, Cooper ST, Sutton RB

Title:

Alternate Splicing of Dysferlin C2A Confers Ca-Dependent and Ca-Independent Binding for Membrane Repair.

Journal:

Structure. 2013 Nov 13. pii: S0969-2126(13)00392-4. doi:, 10.1016/j.str.2013.10.001.

Abstract:

Dysferlin plays a critical role in the Ca2+-dependent repair of microlesions that occur in the muscle sarcolemma. Of the seven C2 domains in dysferlin, only C2A is reported to bind both Ca2+ and phospholipid, thus acting as a key sensor in membrane repair. Dysferlin C2A exists as two isoforms, the "canonical" C2A and C2A variant 1 (C2Av1). Interestingly, these isoforms have markedly different responses to Ca2+ and phospholipid. Structural and thermodynamic analyses are consistent with the canonical C2A domain as a Ca2+-dependent, phospholipid-binding domain, whereas C2Av1 would likely be Ca2+-independent under physiological conditions. Additionally, both isoforms display remarkably low free energies of stability, indicative of a highly flexible structure. The inverted ligand preference and flexibility for both C2A isoforms suggest the capability for both constitutive and Ca2+-regulated effector interactions, an activity that would be essential in its role as a mediator of membrane repair.