Formation and actions of calcium-mobilizing messenger, inositol 1,4,5-trisphosphate
A variety of surface membrane receptors can activate a phospholipase C, which degrades phosphatidylinositol 4,5-bisphosphate liberating a calcium mobilizing second messenger, inositol 1,4,5-trisphosphate ((1,4,5)IP3). The coupling of surface receptors to the phospholipase C involves one or more quanine nucleotide-dependent regulatory proteins that are similar but not identical to those that regulate adenylate cyclase. (1,4,5)IP3 has been shown to release CaS from a portion of the endoplasmic reticulum and is believed responsible for the initial phase of CaS mobilization ascribed to internal CaS release. (1,4,5)IP3 acts by binding to a specific receptor that either is a component of, or regulates, a CaS ion channel. The release of CaS from the (1,4,5)IP3-sensitive component of the endoplasmic reticulum may secondarily activate the second phase of CaS mobilization, which involves CaS entry. (1,4,5)IP3 is metabolized by two pathways. One involves the action of a 5-phosphatase that degrades (1,4,5)IP3 to inositol 1,4-bisphosphate, whereas the other involves a 3-kinase that phosphorylates (1,4,5)IP3 to produce inositol 1,3,4,5-tetrakisphosphate. The significance of this dual metabolism is not known, but it may be important in rapidly extinguishing the CaS -releasing activity (1,4,5)IP3.
- OSTI ID:
- 6285084
- Journal Information:
- Am. J. Physiol.; (United States), Vol. 252:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CALCIUM 45
UPTAKE
INOSITOLS
BIODEGRADATION
RECEPTORS
CHEMICAL ACTIVATION
ATP
CALCIUM COMPOUNDS
CATIONS
CELL MEMBRANES
ENDOPLASMIC RETICULUM
ENZYME INDUCTION
GUINEA PIGS
LIPASE
LIVER CELLS
ORGANIC PHOSPHORUS COMPOUNDS
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METAL COMPOUNDS
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CALCIUM ISOTOPES
CARBOHYDRATES
CARBOXYLESTERASES
CELL CONSTITUENTS
CHARGED PARTICLES
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
DECOMPOSITION
ENZYMES
ESTERASES
EVEN-ODD NUCLEI
GENE REGULATION
HYDROLASES
INTERMEDIATE MASS NUCLEI
IONS
ISOTOPES
MAMMALS
MEMBRANES
MONOSACCHARIDES
NUCLEI
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANOIDS
RADIOISOTOPES
RODENTS
SACCHARIDES
SOMATIC CELLS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques