[The influence of caldesmon on strong binding of myosin with actin in denervated rat skeletal muscles].
The effect of caldesmon (CaD) on conformational changes in F-actin modified by fluorescent probe TRITC-phalloidin was investigated by polarized fluorimetry. Changes were induced by a subfragment-1 (S-1) of myosin in the absence or presence of CaD in ghost muscle fibers obtained from intact and denervated slow (SOL) and fast (EDL) skeletal muscles of rats. S-1 binding to actin of both SOL and EDL muscles was shown to cause changes in polarized parameters of TRITC-phalloidin typical for a strong actin-myosin binding as well as of transition ofactin subunits from "off" to "on" state. CaD inhibits this significantly. Denervation atrophy inhibits the effect of S-1 as well but does not affect the capability of CaD decreasing the formation of strong binding in actomyosin complex. It is supposed that CaD "freezes" F-actin structure in "off" state. The denervation atrophy has no effect on CaD responsibility to bind thin filaments and to switch "off" actin monomers.
Kirillina
V P
VP
Jakubiec-Puka
A
A
Borovikov
Iu S
IuS
D000199:Actins / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D002148:Calmodulin-Binding Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology / Q000502:physiology*; D008297:Male; D009119:Muscle Contraction; D009121:Muscle Denervation; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology*; D015879:Myosin Subfragments / Q000302:isolation & purification / Q000378:metabolism / Q000502:physiology; D009218:Myosins / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D000199:Actins; D002148:Calmodulin-Binding Proteins; D015879:Myosin Subfragments; D009218:Myosins