caa a22 4500 475745213 CHVBK 20180406123511.0 cr unu---uuuuu 170329e20001101xx s 000 0 eng 10.1023/A:1010396429297 doi (NATIONALLICENCE)springer-10.1023/A:1010396429297 Remodeling of the Actin Cytoskeleton in the Contracting A7r5 Smooth Muscle Cell [Elektronische Daten] [M. Fultz, C. Li, W. Geng, G. Wright] It has been proposed that the reorganization of components of the actin cytomatrix could contribute to force development and the low energy cost of sustained contraction in contractile cells which lack a structured sarcomere (A.S. Battistella-Patterson, S. Wang and G.L. Wright (1997) Can J Physiol Pharmacol 75: 1287-1299). However, there has been no direct evidence of an apropos actin reorganization specifically linked to the contractile response in cells of this type. Remodeling of the α- and β-actin domains was studied in A7r5 smooth muscle cells during phorbol 12,13 dibutyrate (PDB)-induced contraction using immunohistologic staining and β-actin-green fluorescent protein (β-actin-GFP) fusion protein expression. Cell stained with phalloidin as well as cells expressing β-actin-GFP showed densely packed actin stress cables, arranged in parallel and extending across the cell body. PDB caused approximately 85% of cells to contract with evidence of forcible detachment from peripheral adhesion sites seen in many cells. The contraction of the cell body was not uniform but occurred along a principal axis parallel to the system of densely packed β-actin cables. During the interval of contraction, the β-actin cables shortened without evidence of disassembly or new cable formation. The use of cytochalasin to inhibit actin polymerization resulted in the dissolution of the actin cables at the central region of the cell and caused the elongation of precontracted cells. In unstimulated cells, α-actin formed cables similar in arrangement to the cell spanning β-actin cables. Within a short interval after PDB addition; however, the majority of α-actin cables disassembled and reformed into intensely fluorescing column-like structures extending vertically from the cell base at the center of clusters of α-actin filaments. The α-actin columns of contracting cells showed strong colocalization of α-actinin suggesting they could be structurally analogous to the dense bodies of highly differentiated smooth muscle cells. The results indicate that the α- and β-actin domains of A7r5 cells undergo a highly structured reorganization during PDB-induced contraction. The extent and nature of this restructuring suggest that remodeling could play a role in contractile function. Kluwer Academic Publishers, 2000 Fultz M. Department of Physiology, The Joan Edwards School of Medicine, Marshall University, 25704, Huntington, WV, USA aut Li C. Department of Physiology, The Joan Edwards School of Medicine, Marshall University, 25704, Huntington, WV, USA aut Geng W. Department of Physiology, The Joan Edwards School of Medicine, Marshall University, 25704, Huntington, WV, USA aut Wright G. Department of Physiology, The Joan Edwards School of Medicine, Marshall University, 25704, Huntington, WV, USA aut Journal of Muscle Research & Cell Motility Kluwer Academic Publishers 21/8(2000-11-01), 775-787 0142-4319 21:8<775 2000 21 10974 https://doi.org/10.1023/A:1010396429297 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1010396429297 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Fultz M. Department of Physiology, The Joan Edwards School of Medicine, Marshall University, 25704, Huntington, WV, USA aut NATIONALLICENCE 700 1- Li C. Department of Physiology, The Joan Edwards School of Medicine, Marshall University, 25704, Huntington, WV, USA aut NATIONALLICENCE 700 1- Geng W. Department of Physiology, The Joan Edwards School of Medicine, Marshall University, 25704, Huntington, WV, USA aut NATIONALLICENCE 700 1- Wright G. Department of Physiology, The Joan Edwards School of Medicine, Marshall University, 25704, Huntington, WV, USA aut NATIONALLICENCE 773 0- Journal of Muscle Research & Cell Motility Kluwer Academic Publishers 21/8(2000-11-01), 775-787 0142-4319 21:8<775 2000 21 10974 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer