Mapping of a myosin-binding domain and a regulatory phosphorylation site in M-protein, a structural protein of the sarcomeric M band.
The myofibrils of cross-striated muscle fibers contain in their M bands cytoskeletal proteins whose main function seems to be the stabilization of the three-dimensional arrangement of thick filaments. We identified two immunoglobin domains (Mp2-Mp3) of M-protein as a site binding to the central region of light meromyosin. This binding is regulated in vitro by phosphorylation of a single serine residue (Ser76) in the immediately adjacent amino-terminal domain Mp1. M-protein phosphorylation by cAMP-dependent kinase A inhibits binding to myosin LMM. Transient transfection studies of cultured cells revealed that the myosin-binding site seems involved in the targeting of M-protein to its location in the myofibril. Using the same method, a second myofibril-binding site was uncovered in domains Mp9-Mp13. These results support the view that specific phosphorylation events could be also important for the control of sarcomeric M band formation and remodeling.
Obermann
W M
WM
Max-Planck-Institute for Biophysical Chemistry, Department of Biochemistry, D-37077 Göttingen, Germany.
van der Ven
P F
PF
Steiner
F
F
Weber
K
K
Fürst
D O
DO
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D002478:Cells, Cultured; D064211:Connectin; D006224:Cricetinae; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D009194:Myeloma Proteins; D009210:Myofibrils / Q000378:metabolism; D009218:Myosins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012518:Sarcomeres / Q000737:chemistry*; D014162:Transfection
D064211:Connectin; D009124:Muscle Proteins; D009194:Myeloma Proteins; D011994:Recombinant Proteins; C085016:multiple myeloma M-proteins; D017868:Cyclic AMP-Dependent Protein Kinases; D009218:Myosins