Expression of sarcomeric proteins and assembly of myofibrils in the putative myofibroblast cell line BHK-21/C13.
The expression and organization patterns of several myofibrillar proteins were analysed in the putative myofibroblast cell line BHK-21/C13. Although this cell line originates from renal tissue, the majority of the cells express titin. In these cells, titin is, under standard culture conditions, detected in myofibril-like structures (MLSs), where it alternates with non-muscle myosin (NMM). Expression of sarcomeric myosin heavy chain (sMyHC) is observed in a small minority of cells, while other sarcomeric proteins, such as nebulin, myosin binding protein C (MyBP-C), myomesin and M-protein are not expressed at all. By changing the culture conditions in a way equal to conditions that induce differentiation of skeletal muscle cells, a process reminiscent of sarcomerogenesis in vitro is induced. Within one day after the switch to a low-nutrition medium, myofibrillar proteins can be detected in a subset of cells, and after two to five days, all myofibrillar proteins examined are organized in typical sarcomeric patterns. Frequently, cross-striations are visible with phase contrast optics. Transfection of these cells with truncated myomesin fragments showed that a specific part of the myomesin molecule, known to contain a titin-binding site, binds to MLSs, whereas other parts do not. These results demonstrate that this cell line could serve as a powerful model to study the assembly of myofibrils. At the same time, its transfectability offers an invaluable tool for in vivo studies concerning binding properties of sarcomeric proteins.
van der Ven
P F
PF
Department of Cell Biology, University of Potsdam, Germany. pvdven@rz.uni-potsdam.de
Fürst
D O
DO
D000818:Animals; D001665:Binding Sites; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D064211:Connectin; D006224:Cricetinae; D003470:Culture Media / Q000494:pharmacology; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D007668:Kidney; D008647:Mesocricetus; D008856:Microscopy, Fluorescence; D009124:Muscle Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D009194:Myeloma Proteins; D009210:Myofibrils / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000096:biosynthesis / Q000235:genetics; D011494:Protein Kinases / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012518:Sarcomeres / Q000378:metabolism*; D014162:Transfection; D000099163:Myosin Binding Protein C
D002352:Carrier Proteins; D064211:Connectin; D003470:Culture Media; D009124:Muscle Proteins; D009194:Myeloma Proteins; D018995:Myosin Heavy Chains; D011494:Protein Kinases; D011993:Recombinant Fusion Proteins; D000099163:Myosin Binding Protein C; C085016:multiple myeloma M-proteins; C035620:nebulin