QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend 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 Welikson, R. E. Articles by Fischman, D. A. Search for Related Content PubMed PubMed Citation Articles by Welikson, R. E. Articles by Fischman, D. A.

The C-terminal IgI domains of myosin-binding proteins C and H (MyBP-C and MyBP-H) are both necessary and sufficient for the intracellular crosslinking of sarcomeric myosin in transfected non-muscle cells

Robert E. Welikson^* and Donald A. Fischman

Department of Cell Biology, Weill Medical College of Cornell University, 1300 York Avenue, York Avenue, New York, NY 10021, USA
^* Present address: Department of Biochemistry, University of Washington, Seattle, WA 98 195, USA

Author for correspondence (e-mail: fisch{at}med.cornell.edu)

Accepted 14 June 2002

Using the COS cell transfection assay developed previously, we examined which domains of myosin-binding proteins C and H (MyBP-C and MyBP-H) are involved in intracellular interactions with sarcomeric myosin heavy chain (MyHC). Earlier studies demonstrated that overexpression of sarcomeric MyHC in COS cells results in the cytoplasmic assembly of anisotropic, spindle-like aggregates of myosin-containing filaments in the absence of other myofibrillar proteins. When the same sarcomeric MyHC was co-expressed with either MyBP-C or MyBP-H, prominent cable-like co-polymers of MyHC and the MyBPs formed in the cytoplasm instead of the spindle-like aggregates formed by MyHC alone. In vitro binding assays have shown that the C-terminal IgI domain of both MyBP-C (domain C10) and MyBP-H (domain H4) contains the light meromyosin (LMM)-binding sites of each molecule, but this domain cannot explain all of the intracellular properties of the molecules. For example, domains C7-C10 of MyBP-C and domains H1-H4 of MyBP-H are required for the faithful targeting of these proteins to the A-bands of myofibrils in skeletal muscle. Using truncation mutants of both MyBPs tagged with either green fluorescent protein (GFP) or c-myc, we now demonstrate that the last four domains of both MyBP-C and MyBP-H colocalize with the full-length proteins in the MyHC/MyBP cable polymers when co-transfected with MyHC in COS cells. Deletion of the C-terminal IgI domain in either MyBP-C or MyBP-H abrogated cable formation, but the expressed proteins could still colocalize with MyHC-containing filament aggregates. Co-expression of only the C-terminal IgI domain of MyBP-C with sarcomeric MyHC was sufficient for cable formation and colocalization with myosin. We conclude that the C-terminal IgI domains of both MyBP-H and MyBP-C are both necessary and sufficient for inducing MyHC/MyBP cable formation in this COS cell system. However, there must be other myosin-binding sites in MyBP-C and MyBP-H that explain the co-distribution of these proteins with myosin filaments in the absence of cable formation. These latter sites are neither sufficient nor required for cable formation.

Key words: C-protein, H-protein, Myosin, Muscle, Myofibril assembly, Immunoglobulin, Light meromyosin

This article has been cited by other articles:

				R. D. S. Dixon, D. K. Arneman, A. S. Rachlin, N. R. Sundaresan, M. J. Costello, S. L. Campbell, and C. A. Otey Palladin Is an Actin Cross-linking Protein That Uses Immunoglobulin-like Domains to Bind Filamentous Actin J. Biol. Chem., March 7, 2008; 283(10): 6222 - 6231. [Abstract] [Full Text] [PDF]

				G. L. Warren, M. Summan, X. Gao, R. Chapman, T. Hulderman, and P. P. Simeonova Mechanisms of skeletal muscle injury and repair revealed by gene expression studies in mouse models J. Physiol., July 15, 2007; 582(2): 825 - 841. [Abstract] [Full Text] [PDF]

				M. J. McGrath, D. L. Cottle, M.-A. Nguyen, J. M. Dyson, I. D. Coghill, P. A. Robinson, M. Holdsworth, B. S. Cowling, E. C. Hardeman, C. A. Mitchell, et al. Four and a Half LIM Protein 1 Binds Myosin-binding Protein C and Regulates Myosin Filament Formation and Sarcomere Assembly J. Biol. Chem., March 17, 2006; 281(11): 7666 - 7683. [Abstract] [Full Text] [PDF]

				E. Flashman, C. Redwood, J. Moolman-Smook, and H. Watkins Cardiac Myosin Binding Protein C: Its Role in Physiology and Disease Circ. Res., May 28, 2004; 94(10): 1279 - 1289. [Abstract] [Full Text] [PDF]

				N. G. Dulyaninova, Y. V. Patskovsky, and A. R. Bresnick The N-terminus of the long MLCK induces a disruption in normal spindle morphology and metaphase arrest J. Cell Sci., March 15, 2004; 117(8): 1481 - 1493. [Abstract] [Full Text] [PDF]

				J. Flavigny, P. Robert, J.-C. Camelin, K. Schwartz, L. Carrier, and I. Berrebi-Bertrand Biomolecular interactions between human recombinant {beta}-MyHC and cMyBP-Cs implicated in familial hypertrophic cardiomyopathy Cardiovasc Res, November 1, 2003; 60(2): 388 - 396. [Abstract] [Full Text] [PDF]

				N. Sato, T. Kawakami, A. Nakayama, H. Suzuki, H. Kasahara, and T. Obinata A Novel Variant of Cardiac Myosin-binding Protein-C That Is Unable to Assemble into Sarcomeres Is Expressed in the Aged Mouse Atrium Mol. Biol. Cell, August 1, 2003; 14(8): 3180 - 3191. [Abstract] [Full Text] [PDF]