J. Biochem, 1981, Vol. 89, No. 1 297-310
© 1981 Japanese Biochemical Society
research-article |
Eu-Actinin, a New Structural Protein of the Z-Line of Striated Muscles1
*Institute of Basic Medical Sciences, The University of Tsukuba Sakura-mura, Niihari-gun, Ibaraki 305
**Tokyo Metropolitan Institute of Medical Sciences Bunkyo-ku, Tokyo 113
A new protein component of the Z-line of striated muscles was isolated from chicken breast muscle. This protein has been designated as eu-actinin because of its close similarity in polypeptide molecular weight to actin. Eu-actinin was extracted from myosin-removed myofibrils at low ionic strength at pH 6.5 and purified by column chromatography on Sepharose 4B and DEAE-cellulose. Although the polypeptide molecular weight of eu-actinin measured by SDS-polyacrylamide gel electrophoresis is similar to that of actin, other physico-chemical properties of eu-actinin definitely differ from those of actin. The isoelectric point of eu-actinin was more acidic than that of actin. The amino acid composition of eu-actinin was found to be different from that of actin or those of other muscle structural proteins. The results of analytical gel filtration on Sepharose 4B indicated that eu-actinin forms dimers through non-covalent bonding under aqueous conditions. Eu-actinin has a low axial asymmetry under low-salt conditions, as judged from its intrinsic viscosity (
]=6.4 ml/g for the dimer state) and exhibits a tendency to undergo self-association with increasing ionic strength.
Interactions of eu-actinin with other muscle proteins were examined by the affinity column technique. It was shown that eu-actinin binds to actin and 
-actinin. Eu-actinin exhibited strong seeding ability for the polymerization of actin.
Antibody to eu-actinin was raised in a goat and purified by affinity chromatography. The specific antibody against eu-actinin did not form precipitine lines with actin or -actinin. Immunofluorescence studies revealed that eu-actinin is localized at the Z-line of myofibrils. The FITC-conjugated antibody to eu-actinin also stained the Z-lines of rabbit skeletal muscle and chicken cardiac muscle. Therefore, it was concluded that eu-actinin is a new, ubiquitous constituent of Z-lines of striated muscles.
1 This study was supported in part by a grant from the Ministry of Education, Science and Culture of Japan.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  A. Terasaki, H Nakagawa, E Kotani, H Mori, and K Ohashi A high molecular mass protein isolated from chicken gizzard: its localization at the dense plaques and dense bodies of smooth muscle and the Z-disks of skeletal muscle J. Cell Sci., January 3, 1995; 108(3): 857 - 868. [Abstract] [PDF]
|
|