Dependence of calmodulin localization in the retina on the NINAC unconventional myosin.
Calmodulin is a highly conserved regulatory protein found in all eukaryotic organisms which mediates a variety of calcium ion-dependent signalling pathways. In the Drosophila retina, calmodulin was concentrated in the photoreceptor cell microvillar structure, the rhabdomere, and was found in lower amounts in the sub-rhabdomeral cytoplasm. This calmodulin localization was dependent on the NINAC (neither inactivation nor afterpotential C) unconventional myosins. Mutant flies lacking the rhabdomere-specific p174 NINAC protein did not concentrate calmodulin in the rhabdomere, whereas flies lacking the sub-rhabdomeral p132 isoform had no detectable cytoplasmic calmodulin. Furthermore, a defect in vision resulted when calmodulin was not concentrated in the rhabdomeres, suggesting a role for calmodulin in the regulation of fly phototransduction. A general function of unconventional myosins may be to control the subcellular distribution of calmodulin.
Porter
J A
JA
Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205.
Yu
M
M
Doberstein
S K
SK
Pollard
T D
TD
Montell
C
C
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002147:Calmodulin / Q000378:metabolism*; D004330:Drosophila; D029721:Drosophila Proteins; D004596:Electroretinography; D005136:Eye Proteins / Q000378:metabolism*; D009154:Mutation; D018995:Myosin Heavy Chains; D009218:Myosins / Q000378:metabolism*; D009410:Nerve Degeneration; D017956:Photoreceptor Cells, Invertebrate / Q000378:metabolism*; D012160:Retina / Q000378:metabolism
D002147:Calmodulin; D029721:Drosophila Proteins; D005136:Eye Proteins; C072308:ninaC protein, Drosophila; D018995:Myosin Heavy Chains; D009218:Myosins; D002118:Calcium