Function of the syndecan-4 cytoplasmic domain in oligomerization and association with α-actinin in turkey muscle satellite cells
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Syndecan-4 (S4) is a cell membrane heparan sulfate proteoglycan that plays a role in satellite cell mediated myogenesis. S4 modulates the proliferation of myogenic satellite cells, but the mechanism of how S4 functions during myogenesis is not well understood. In other cell systems, S4 has been shown to form oligomers in the cell membrane and interact through its cytoplasmic domain with the cytoskeletal protein α-actinin. This study addressed if S4 forms oligomers and interacts with α-actinin in muscle. The S4 cytoplasmic domain was found to interact with α-actinin in a phosphatidylinositol-4,5-bisphosphate dependent manner, but did not associate with vinculin. Through confocal microscopy, both S4 and syndecan-4 without the cytoplasmic domain were localized to the cell membrane. Although the cytoplasmic domain was necessary for the interaction with α-actinin, S4 oligomer formation occurred in the absence of the cytoplasmic domain. These data indicated that S4 function in skeletal muscle is mediated through the formation of oligomers and interaction with the cytoskeletal protein α-actinin.
Keywordsα-Actinin Muscle Oligomers Satellite cell Syndecan-4
Bovine serum albumin
Fibroblast growth factor 2
Protein kinase C α
Polyvinylidene fluoride membrane
Small interfering RNA
Sodium dodecyl sulfate-polyacrylamide gel
Syndecan-4 without the cytoplasmic domain
Tris-buffered saline containing Tween 20
Salary and partial research support to S.G.V. was provided by state and federal funds appropriated to the Ohio Agricultural Research and Development Center, The Ohio State University, the Midwest Poultry Research Consortium to S.G.V. and D.C.M., National Institute of Food and Agriculture Multistate Project NC-1184 to S.G.V. and D.C.M, and National Research Initiative Competitive Grant no. 2009-35503-05176 to S.G.V. from the USDA National Institute of Food and Agriculture.
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