Formation and actions of inositol phosphates

Conference · Thu May 01 04:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:6527512

Putney, Jr, J W

A wide variety of hormone and neurotransmitter receptors mediate control of cell function through activation of a phosphodiesteratic breakdown of polyphosphoinositides. In electrically permeabilized pancreatic acinar cells, non-hydrolyzable derivatives of GTP can activate this phosphodiesterase, and potentiate the action of hormones. This suggests receptor coupling to the enzyme probably involves a guanine nucleotide-dependent regulatory protein analogous to the ones involved in regulating adenylate cyclase. The water-soluble product of this reaction inositol-1,4,5-tris-phosphate ((1,4,5)IP/sub 3/), signals Ca/sup 2 +/ release from a fraction of the endoplasmic reticulum which, in the liver, constitutes about 40% of the non-mitochondrial Ca/sup 2 +/ accumulating activity. By using a high specific activity /sup 32/P-labelled (1,4,5)IP/sub 3/, a specific and saturable binding site for (1,4,5)IP/sub 3/ can be demonstrated. Binding of (1,4,5)IP/sub 3/ and (2,4,5)IP/sub 3/ to this site is well correlated with the Ca/sup 2 +/-releasing actions of these molecules. This may indicate that the actions of (1,4,5)IP/sub 3/ are mediated by a specific receptor on the endo- plasmic reticulum. The emptying of the sensitive Ca/sup 2 +/-pool in the endoplasmic reticulum by (1,4,5)IP/sub 3/ may secondarily signal the influx of Ca/sup 2 +/ from the extracellular space.

• Research Organization: Medical College of Virginia, Richmond
• OSTI ID: 6527512
• Report Number(s): CONF-8606151-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:6
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALINE EARTH METAL COMPOUNDS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BODY
CALCIUM COMPOUNDS
CARBOHYDRATES
CATIONS
CELL CONSTITUENTS
CHARGED PARTICLES
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
ENDOCRINE GLANDS
ENDOPLASMIC RETICULUM
GLANDS
INOSITOL
INOSITOLS
IONS
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LIGHT NUCLEI
LIVER
MEMBRANE PROTEINS
MONOSACCHARIDES
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANOIDS
ORGANS
OXYGEN COMPOUNDS
PANCREAS
PHOSPHATES
PHOSPHORUS 32
PHOSPHORUS COMPOUNDS
PHOSPHORUS ISOTOPES
PROTEINS
RADIOISOTOPES
REACTION KINETICS
RECEPTORS
SACCHARIDES
TRACER TECHNIQUES