We have cloned a new mammalian unconventional myosin, porcine myosin-VI from the proximal tubule cell line, LLC-PK1 (CL4). Porcine myosin-VI is highly homologous to Drosophila 95F myosin heavy chain, and together these two myosins comprise a sixth class of myosin motors. Myosin-VI exhibits ATP-sensitive actin-binding activities characteristic of myosins, and it is associated with a calmodulin light chain. Within LLC-PK1 cells, myosin-VI is soluble and does not associate with the major actin-containing domains. Within the kidney, however, myosin-VI is associated with sedimentable structures and specifically locates to the actin- and membrane-rich apical brush border domain of the proximal tubule cells. This motor was not enriched within the glomerulus, capillaries, or distal tubules. Myosin-VI associates with the proximal tubule cytoskeleton in an ATP-sensitive fashion, suggesting that this motor is associated with the actin cytoskeleton within the proximal tubule cells. Given the difference in association of myosin-VI with the apical cytoskeleton between LLC-PK1 cells and adult kidney, it is likely that this cell line does not fully differentiate to form functional proximal tubule cells. Myosin-VI may require the presence of additional elements, only found in vivo in proximal tubule cells, to properly locate to the apical domain.
Article|
October 15 1994
Porcine myosin-VI: characterization of a new mammalian unconventional myosin.
T Hasson,
T Hasson
Department of Biology, Yale University, New Haven, Connecticut 06520.
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M S Mooseker
M S Mooseker
Department of Biology, Yale University, New Haven, Connecticut 06520.
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T Hasson
Department of Biology, Yale University, New Haven, Connecticut 06520.
M S Mooseker
Department of Biology, Yale University, New Haven, Connecticut 06520.
Online Issn: 1540-8140
Print Issn: 0021-9525
J Cell Biol (1994) 127 (2): 425–440.
Citation
T Hasson, M S Mooseker; Porcine myosin-VI: characterization of a new mammalian unconventional myosin.. J Cell Biol 15 October 1994; 127 (2): 425–440. doi: https://doi.org/10.1083/jcb.127.2.425
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