Uncoordinated expression of myosin heavy chains and myosin-binding protein C isoforms in human extraocular muscles
2006 (English)In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, Vol. 47, no 10, 4188-4193 p.Article in journal (Refereed) Published
PURPOSE: To examine the distribution of myosin-binding protein C (MyBP-C) in human extraocular muscles (EOMs) and to correlate the myosin heavy chain (MyHC) and the MyBP-C composition of the fibers. METHODS: Samples from 17 EOMs, 3 levator palpebrae (LP), and 6 limb muscles were analyzed with SDS-PAGE and immunoblot or processed for immunocytochemistry with monoclonal antibodies (mAbs) against MyBP-C-fast, MyBP-C-slow, MyHCIIa, MyHCI, MyHCsto, MyHCalpha-cardiac, and MyHCemb. RESULTS: In the limb muscle samples, fast fibers were labeled with anti-MyBP-C-fast and anti-MyBP-C-slow, whereas the slow fibers were immunostained with anti-MyBP-C-slow only, in accordance with previous studies. In 11 EOM samples MyBP-C-fast was not detected, and weak staining with anti-MyBP-C-fast was seen only in a few fibers in the proximal part of 2 muscles. The mAb against MyBP-C-slow labeled all fibers, but fibers containing MyHCI were generally more strongly stained. In the levator palpebrae, immunostaining with anti-MyBP-C-fast was present in some fibers labeled with anti-MyHCIIa and/or anti-MyHCeom. MyBP-C-fast and -intermediate were not detected biochemically in the EOMs. CONCLUSIONS: The lack of MyBP-C-fast and intermediate is an additional feature of the human EOM allotype. The true EOMs have a unique myofibrillar protein isoform composition reflecting their special structural and functional properties. The levator palpebrae muscle phenotype is intermediate between that of the EOMs and the limb muscles.
Place, publisher, year, edition, pages
Association for Research in Vision and Ophthalmology , 2006. Vol. 47, no 10, 4188-4193 p.
Adolescent, Adult, Aged; 80 and over, Antibodies; Monoclonal, Carrier Proteins/*metabolism, Electrophoresis; Polyacrylamide Gel, Female, Humans, Immunoblotting, Immunohistochemistry, Male, Muscle; Skeletal/metabolism, Myosin Heavy Chains/*metabolism, Myosins/metabolism, Oculomotor Muscles/*metabolism, Protein Isoforms
IdentifiersURN: urn:nbn:se:umu:diva-12672DOI: 10.1167/iovs.05-1496PubMedID: 17003405OAI: oai:DiVA.org:umu-12672DiVA: diva2:152343