Different obscurin isoforms localize to distinct sites at sarcomeres

Bowman, Amber L.; Kontrogianni-Konstantopoulos, Aikaterini; Hirsch, Sara S.; Geisler, Sarah B.; Gonzalez-Serratos, Hugo; Russell, Mark W.; Bloch, Robert J.

doi:10.1016/j.febslet.2007.03.011

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Volume 581, Issue 8 , Pages 1549-1554, 17 April 2007

Different obscurin isoforms localize to distinct sites at sarcomeres

Edited by Michael R. Bubb

Amber L. Bowman
- Department of Physiology, University of Maryland School of Medicine, 655 W. Baltimore St, MD 21201, USA
Aikaterini Kontrogianni-Konstantopoulos
- Department of Physiology, University of Maryland School of Medicine, 655 W. Baltimore St, MD 21201, USA
Sara S. Hirsch
- Department of Physiology, University of Maryland School of Medicine, 655 W. Baltimore St, MD 21201, USA
Sarah B. Geisler
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI, USA
Hugo Gonzalez-Serratos
- Department of Physiology, University of Maryland School of Medicine, 655 W. Baltimore St, MD 21201, USA
Mark W. Russell
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI, USA
Robert J. Bloch
- Department of Physiology, University of Maryland School of Medicine, 655 W. Baltimore St, MD 21201, USA
- Corresponding author. Fax: +1 410 706 8341.

Received 19 February 2007; accepted 8 March 2007. published online 15 March 2007.

Abstract

We used four antibodies to regions of obscurin isoforms A and B, encoded by the obscurin gene, to investigate the location of these proteins in skeletal myofibers at resting and stretched lengths. Obscurin A (∼800kDa) which was recognized by antibodies generated to the N-terminal, Rho-GEF, and the non-modular C-terminal domain that lacks the kinase-like domains, localizes at the level of the M-band. Obscurin B (∼900kDa) which has the N-terminal, Rho-GEF, and the C-terminal kinase-like domains, localizes at the level of the A/I junction. Additional isoforms, which lack one or more of these epitopes, are present at the Z-disk and Z/I junction.