Protection against osmotic stress by cGMP-mediated myosin phosphorylation.
Conventional myosin functions universally as a generator of motive force in eukaryotic cells. Analysis of mutants of the microorganism Dictyostelium discoideum revealed that myosin also provides resistance against high external osmolarities. An osmo-induced increase of intracellular guanosine 3',5'-monophosphate was shown to mediate phosphorylation of three threonine residues on the myosin tail, which caused a relocalization of myosin required to resist osmotic stress. This redistribution of myosin allowed cells to adopt a spherical shape and may provide physical strength to withstand extensive cell shrinkage in high osmolarities.
Kuwayama
H
H
Department of Biochemistry, University of Groningen, Netherlands.
Ecke
M
M
Gerisch
G
G
Van Haastert
P J
PJ
D008841:Actin Cytoskeleton / Q000737:chemistry; D000199:Actins / Q000032:analysis; D000818:Animals; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D003593:Cytoplasm / Q000737:chemistry; D004023:Dictyostelium / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D005947:Glucose / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000378:metabolism; D009218:Myosins / Q000032:analysis / Q000378:metabolism*; D009997:Osmotic Pressure; D010766:Phosphorylation; D011554:Pseudopodia / Q000737:chemistry / Q000648:ultrastructure; D013912:Threonine / Q000378:metabolism; D014882:Water-Electrolyte Balance
D000199:Actins; D013912:Threonine; C016276:8-bromocyclic GMP; D009218:Myosins; D006162:Guanylate Cyclase; D006152:Cyclic GMP; D005947:Glucose