TY - JOUR
T1 - Tropomyosin-enriched and alpha-actinin-enriched microfilaments isolated from chicken embryo fibroblasts by monoclonal antibodies
AU - Lin, J. J.C.
AU - Matsumura, F.
AU - Yamashiro Matsumura, S.
PY - 1984
Y1 - 1984
N2 - Antitropomyosin and anti-alpha-actinin monoclonal antibodies have been used to isolate two classes of microfilaments, i.e., tropomyosin-enriched and alpha-actinin-enriched microfilaments, respectively, from cultured chicken embryo fibroblasts. Electron microscopic studies of the isolated tropomyosin-enriched microfilaments showed periodic localization of tropomyosin along the microfilaments, with a 35-nm repeat. On the contrary, the isolated alpha-actinin-enriched microfilaments showed no obvious periodicity. Many individual alpha-actinin-enriched microfilaments with length >1 μm (ranging from 1 to 10 μm) were aggregated by anti-alpha-actinin monoclonal antibodies. Both of the isolatd microfilaments had the ability to activate the Mg2+-ATPase activity of skeletal muscle myosin, although different extents of activation were observed. These two classes of microfilaments also differed in their protein composition. Molar ratios of major identifiable proteins in the isolated microfilaments were alpha-actinin(dimer):actin(monomer):tropomyosin(dimer) = <0.02:8.06:1.00 for tropomyosin-enriched microfilaments and 0.44:13.91:1.00 for alpha-actinin-enriched microfilaments. By two-dimensional gel analysis of the isolated microfilaments, we have found seven spots which possess typical tropomyosin properties including pl 4.5, immunological cross-reaction, lack of proline and tryptophan, and heat stability. Pulse-chase experiments suggested that the assembly of microfilament-associated proteins, at least for alpha-actinin and tropomyosins, was coordinately regulated by the assembly of actin into microfilaments.
AB - Antitropomyosin and anti-alpha-actinin monoclonal antibodies have been used to isolate two classes of microfilaments, i.e., tropomyosin-enriched and alpha-actinin-enriched microfilaments, respectively, from cultured chicken embryo fibroblasts. Electron microscopic studies of the isolated tropomyosin-enriched microfilaments showed periodic localization of tropomyosin along the microfilaments, with a 35-nm repeat. On the contrary, the isolated alpha-actinin-enriched microfilaments showed no obvious periodicity. Many individual alpha-actinin-enriched microfilaments with length >1 μm (ranging from 1 to 10 μm) were aggregated by anti-alpha-actinin monoclonal antibodies. Both of the isolatd microfilaments had the ability to activate the Mg2+-ATPase activity of skeletal muscle myosin, although different extents of activation were observed. These two classes of microfilaments also differed in their protein composition. Molar ratios of major identifiable proteins in the isolated microfilaments were alpha-actinin(dimer):actin(monomer):tropomyosin(dimer) = <0.02:8.06:1.00 for tropomyosin-enriched microfilaments and 0.44:13.91:1.00 for alpha-actinin-enriched microfilaments. By two-dimensional gel analysis of the isolated microfilaments, we have found seven spots which possess typical tropomyosin properties including pl 4.5, immunological cross-reaction, lack of proline and tryptophan, and heat stability. Pulse-chase experiments suggested that the assembly of microfilament-associated proteins, at least for alpha-actinin and tropomyosins, was coordinately regulated by the assembly of actin into microfilaments.
UR - http://www.scopus.com/inward/record.url?scp=0021335093&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0021335093&partnerID=8YFLogxK
U2 - 10.1083/jcb.98.1.116
DO - 10.1083/jcb.98.1.116
M3 - Article
C2 - 6538570
AN - SCOPUS:0021335093
SN - 0021-9525
VL - 98
SP - 116
EP - 127
JO - Journal of Cell Biology
JF - Journal of Cell Biology
IS - 1
ER -