Isolation and properties of white skeletal muscle alpha-actinin from sea-trout (Salmo trutta) and bass (Dicentrarchus labrax).
Fish alpha-actinin purified from sea-trout and bass white muscle by means of two different extraction procedures was used to investigate the eventual presence of different muscle isoforms in Z-disks. These fish alpha-actinins have the same apparent molecular weight (100 kDa) and the same isoelectric point (pI = 5.6), and also have a total antigenic identity towards anti-bass and anti-chicken alpha-actinin antibodies, suggesting a single molecular species. The role of fish alpha-actinin as an anchorage site for thin actin filaments and elastic titin filaments in Z-bands was studied. Despite conservation of the actin-binding site, fish alpha-actinin has a better actin-binding ability (kD = 0.3 microM) than chicken smooth muscle alpha-actinin (kD = 1.6 microM). Several other structural and functional characteristics of fish alpha-actinin were also studied: conservation of sequence and domain structure, the role of divalent ions (Ca2+, Mg2+) and the dielectric constant of the medium in alpha-actinin-actin interaction. Although the reason for fish white muscle alpha-actinin's close affinity to actin was not clearly established, our results suggested that the physicochemical environment of the Z-filaments in Z-disks might be crucial.
Papa
I
I
UPR 9008 (CNRS), U. 249 (INSERM), Laboratoire de Recherche sur la Motilité Cellulaire, (EPHE), Université de Montpellier I, France.
Méjean
C
C
Lebart
M C
MC
Astier
C
C
Roustan
C
C
Benyamin
Y
Y
Alvarez
C
C
Verrez-Bagnis
V
V
Fleurence
J
J
D000185:Actinin / Q000302:isolation & purification* / Q000378:metabolism; D000199:Actins / Q000378:metabolism; D000818:Animals; D001492:Bass; D004591:Electrophoresis, Polyacrylamide Gel; D008970:Molecular Weight; D018656:Muscle Fibers, Fast-Twitch / Q000378:metabolism*; D014337:Trout
D000199:Actins; D000185:Actinin