RIC, a calmodulin-binding Ras-like GTPase.
Neuronal activity dramatically increases the concentration of cytosolic Ca2+, which then serves as a second messenger to direct diverse cellular responses. Calmodulin is a primary mediator of Ca2+ signals in the nervous system. In a screen for calmodulin-binding proteins, we identified RIC, a protein related to the Ras subfamily of small GTPases. In addition to the ability to bind calmodulin, a number of unique features distinguished RIC from other Ras-like GTPases, including the absence of a signal for prenylation and a distinct effector (G2) domain. Furthermore, we describe two human proteins, RIN and RIT, which were 71% and 66% identical to RIC respectively, shared related G2 domains with RIC, and lacked prenylation signals, suggesting that the RIC family is conserved from flies to humans. While Ric and RIT were widely expressed, expression of RIN was confined to the neuron system.
Wes
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PD
Department of Biological Chemistry, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA.
Yu
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M
Montell
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D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D001921:Brain / Q000378:metabolism; D002148:Calmodulin-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D017124:Conserved Sequence; D017931:DNA Primers / Q000235:genetics; D004330:Drosophila; D020558:GTP Phosphohydrolases / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D020559:Monomeric GTP-Binding Proteins; D009474:Neurons / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D018631:ras Proteins / Q000235:genetics / Q000378:metabolism*
D002148:Calmodulin-Binding Proteins; D017931:DNA Primers; C102569:RIC protein, Drosophila; D020558:GTP Phosphohydrolases; D020559:Monomeric GTP-Binding Proteins; D018631:ras Proteins