A redistribution of actin and myosin IIA accompanies Ca(2+)-dependent insulin secretion.
The study addressed the functional link between remodelling of the actomyosin cytoskeleton in pancreatic beta-cells and the regulation of insulin secretion. Confocal microscopy revealed that myosin heavy chain (MHC) IIA co-localized very well with filamentous (F)-actin in RINm5F cells but MHCIIB did not. Subcellular localization of MHCIIB was not altered by stimulation with 30 mM KCl (which evokes Ca(2+)-dependent insulin secretion). In contrast MHCIIA redistributed in a manner similar to F-actin, especially towards the apical surface, but also away from peripheral regions towards cell contact points on the basal surface. Finally, Ca(2+)-dependent insulin secretion was inhibited by stabilization of actin filaments with jasplakinolide. The results support a role for the MHCIIA/actin cytoskeleton in regulating insulin secretion.
Garvan Institute of Medical Research, Darlinghurst, Australia.
J R
JR
Wilson
R I
RI
Ludowyke
T J
TJ
Biden
D000199:Actins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism*; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism*; D009218:Myosins / Q000378:metabolism*; D010766:Phosphorylation; D013347:Subcellular Fractions
D000199:Actins; D007328:Insulin; D009218:Myosins