Non-genomic signal transduction pathway of vitamin D in muscle.
The secosteroid hormone 1,25(OH)2-vitamin D3 rapidly activates voltage-dependent Ca2+ channels of the L-type in skeletal and cardiac muscle cells by a non-genomic mechanism which involves guanine nucleotide binding (G) protein-medicated stimulation of the adenylate cyclase/cAMP/protein kinase A messenger system. Modifications in calmodulin intracellular distribution induced by PKA-dependent membrane protein phosphorylation may participate in the fast regulation of muscle Ca2+ influx by 1,25(OH)2D3. The protein kinase C pathway also plays a role modulating 1,25(OH)2D3 signal transduction in muscle by cross-talk with the PKA system. The hormone sequentially activates phospholipases C and D providing diacylglycerol for PKC activation and inositol triphosphate for intracellular Ca2+ mobilization. In addition, 1,25(OH)2D3 rapidly stimulates phospholipase A2 generating arachidonic acid for the eicosanoid pathway. Specificity of hormone effects suggests that binding to a muscle membrane-bound receptor mediates these events.
De Boland
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AR
Departamento de Biologia, Universidad Nacional del Sur, Bahia Blanca, Argentina.
Boland
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RL
D000818:Animals; D002117:Calcitriol / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels; D000242:Cyclic AMP; D009132:Muscles / Q000378:metabolism*; D015398:Signal Transduction
D015220:Calcium Channels; D000242:Cyclic AMP; D002117:Calcitriol; D002118:Calcium