A novel nonmuscle alpha-actinin. Purification and characterization of chicken lung alpha-actinin.
Two distinct alpha-actinin-like proteins were detected in chicken lung extract by immunoblot analysis with monoclonal antibodies against alpha-actinin. The mobilities of these proteins on SDS-polyacrylamide gel electrophoresis are very close (approximately 100 kDa). On SDS-polyacrylamide gel electrophoresis in the presence of 6 M urea, however, one of the proteins migrates at 115 kDa and is clearly separated from the other protein (105 kDa). The 115-kDa protein was purified and shown to have at least three unique amino acid sequences which were not detected in other kinds of alpha-actinins: one locates at the extreme NH2-terminal region, and the others locate at the COOH-terminal half region. Immunoblot and proteolytic cleavage analyses revealed that the 115-kDa protein has structural divergence at the COOH-terminal region that includes Ca(2+)-binding EF-hand motifs. Falling-ball viscometric studies showed that although the 115-kDa protein-induced gelation of F-actin is sensitive to Ca2+, the gelation activity of the 115-kDa protein is much higher than that of Ca(2+)-insensitive gizzard alpha-actinin regardless of Ca2+. This indicates that the 115-kDa protein is distinct from other nonmuscle alpha-actinins by its Ca2+ sensitivity.
Imamura
M
M
Institute of Basic Medical Sciences, University of Tsukuba, Ibaraki, Japan.
Masaki
T
T
D000185:Actinin / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D000199:Actins / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002645:Chickens; D002845:Chromatography; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D002918:Chymotrypsin; D017886:Durapatite; D004591:Electrophoresis, Polyacrylamide Gel; D006882:Hydroxyapatites; D015151:Immunoblotting; D007700:Kinetics; D008168:Lung / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009130:Muscle, Smooth / Q000378:metabolism*; D009132:Muscles / Q000378:metabolism*; D010446:Peptide Fragments / Q000302:isolation & purification; D017386:Sequence Homology, Amino Acid
D000199:Actins; D006882:Hydroxyapatites; D010446:Peptide Fragments; D000185:Actinin; D017886:Durapatite; D002918:Chymotrypsin; D002118:Calcium