2001/12/01 by Michael Bárány, John T. Barron, Liping Gu +1 · 1 citation
Biochemistry, Genetics and Molecular Biology · Medicine · Chemistry · #Cellular Mechanics and Interactions #Cardiomyopathy and Myosin Studies #Cell Adhesion Molecules Research #Actin #Nucleotide #Chemistry #Cardiology #Anatomy #Biology #Biochemistry #Medicine #Gene
paper · pdf · doi:10.1074/jbc.m106227200
openalex publication_date 2001/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/04
The actin-bound ADP was separated from cytoplasmic nucleotides by treatment of intact arterial smooth muscle with 50% ethanol. In (32)P-labeled smooth muscle the actin-bound ADP and phosphate readily exchanged with the cytoplasmic [gamma,beta-(32)P]ATP; the specific radioactivity of actin-bound ADP was equal to that of the beta-phosphate of cytoplasmic ATP and the specific radioactivity of actin-bound phosphate was equal to that of the gamma-phosphate of cytoplasmic ATP. In contrast, the exchange of the actin-bound ADP in skeletal muscle was very slow. The presence of cytoplasmic ATP was required for the exchange of the actin-bound ADP and phosphate; if ATP synthesis was inhibited the exchange was also inhibited. The extent of exchange was reduced in muscles contracted by histamine or K(+), as compared with resting muscles. The exchange was also shown in other mammalian smooth muscles, uterus, urinary bladder, and stomach. The data indicate a dynamic state of actin in smooth muscle. The data also suggest that polymerization-depolymerization of actin is part of the contraction-relaxation cycle of smooth muscle.