Artículo de revista
Phosphorylation of phosphatidylinositol by transverse tubule vesicles and its possible role in excitation-contraction coupling
Fecha
1986Registro en:
FEBS Letters, Volumen 202, Issue 1, 2018, Pages 69-73
00145793
10.1016/0014-5793(86)80651-2
Autor
Hidalgo Tapia, María Cecilia
Carrasco, María Angélica
Magendzo, Karin
Jaimovich Pérez, Enrique
Institución
Resumen
Phosphorylation of phosphatidylinositol to phosphatidylinositol 4-monophosphate and to phosphatidyl-inositol 4,5-bisphosphate was demonstrated in transverse-tubule membranes isolated from frog skeletal muscle using [γ-32P]ATP as substrate. At millimolar concentrations of Mg2+ both phosphorylation reactions were completed within 15 s at 25°C. Isolated sarcoplasmic reticulum vesicles phosphorylated phosphatidyl-inositol to phosphatidylinositol 4-phosphate with a lower specific activity than the transverse tubules, and lacked the ability to produce phosphatidylinositol 4,5-bisphosphate. These findings show, for the first time, that isolated transverse-tubule membranes carry out one of the steps required to sustain a role for inositol trisphosphate as the physiological messenger in excitation-contraction coupling in skeletal muscle. The finding that 0.5 mM tetracaine apparently inhibits the phosphorylation of phosphatidylinositol 4-phosphate to phosphatidylinositol 4,5-bisphosphate also su