Disruption of the filamentous actin cytoskeleton is necessary for the activation of capacitative calcium entry in naive smooth muscle cells.
It has been proposed that cytoskeleton plays a key positive role in the activation of capacitative calcium entry (CCE), which supported the secretion-like hypothesis for the mechanisms underlying this process. However, its role on CCE in native smooth muscle is unknown. Here we demonstrate that CCE in isolated gallbladder myocytes was enhanced by cytochalasin D or latrunculin A treatments (agents that cause actin disassembly) whereas it was reduced by jasplakinolide treatment (which causes actin polymerization), suggesting that actin cytoskeleton acts as a barrier in CCE. In addition, we show for the first time that depletion of intracellular Ca2+ stores by thapsigargin and cholecystokinin in BAPTA-loaded cells induced a decrease in F-actin content that was consistent with a link between CCE and actin reorganization. In conclusion, these data suggest an active participation of actin reorganization in the implementation of CCE and support a conformational coupling model for this process in naive smooth muscle cells.
Morales
Sara
S
Department of Physiology, University of Extremadura, 10071 Cáceres, Spain.
Camello
Pedro J
PJ
Rosado
Juan A
JA
Mawe
Gary M
GM
Pozo
María J
MJ
D008841:Actin Cytoskeleton / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D000199:Actins / Q000032:analysis; D000818:Animals; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D015638:Cytochalasin D / Q000494:pharmacology; D047630:Depsipeptides / Q000494:pharmacology; D005704:Gallbladder / Q000166:cytology; D006168:Guinea Pigs; D017136:Ion Transport; D008297:Male; D009130:Muscle, Smooth / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D013844:Thiazoles / Q000494:pharmacology; D053778:Thiazolidines
D000199:Actins; D019086:Bridged Bicyclo Compounds, Heterocyclic; D047630:Depsipeptides; D013844:Thiazoles; D053778:Thiazolidines; C057531:jasplakinolide; D015638:Cytochalasin D; C037067:latrunculin A; D002118:Calcium