Mechanisms of calcium release induced by GTP and inositol 1,4,5-trisphosphate

Conference · Fri May 01 04:00:00 EDT 1987 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:6079988

Gill, D L; Chueh, S H; Mullaney, J M; Mallet, M K

Recent studies show that Ca/sup 2 +/ efflux from ER is controlled by a sensitive and specific guanine nucleotide regulatory mechanism. Using microsomes of permeabilized cells derived from N1E-115 neuroblastoma or DDT/sub 1/MF-2 smooth muscle cell lines, both GTP and IP/sub 3/ effect Ca/sup 2 +/ release from a common intracellular pool; however, the mechanisms of activation of Ca/sup 2 +/ release by the two agents appear distinct with regard to several parameters. Studies using liver microsomes are currently investigating whether similar distinctions between the actions of IP/sub 3/ and GTP exist in other cell types. At present it is unknown if GTP-activated Ca/sup 2 +/ release is mediated by a G-protein-like activity. Studies indicate that such release is not altered by pertussis toxin. Since GTP..gamma..S is inactive and blocks the action of GTP, a modified G-protein activation process must be invoked. Current investigations are attempting to identify the protein(s) involved in GTP-mediated Ca/sup 2 +/ release by direct photo-crosslinking experiments using (..cap alpha..-/sup 32/P)GTP. Successful labeling of many nucleotide-binding proteins has been accomplished; most but not all labeling is displaced by ATP. GTP-specifically labeled proteins are being assessed as candidates for the GTP-mediated release process.

• Research Organization: Univ. of Maryland School of Medicine, Baltimore
• OSTI ID: 6079988
• Report Number(s): CONF-870644-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 46:6
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALINE EARTH METAL COMPOUNDS
ANIMAL CELLS
ANTIGENS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL FUNCTIONS
BODY
CALCIUM COMPOUNDS
CARBOHYDRATES
CELL CONSTITUENTS
CHEMICAL REACTIONS
CROSS-LINKING
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
FUNCTIONS
GLANDS
GUANYLIC ACID
INOSITOL
INOSITOLS
ISOTOPE APPLICATIONS
ISOTOPES
LABELLING
LIGHT NUCLEI
LIVER
MATERIALS
MEMBRANE TRANSPORT
MICROSOMES
MONOSACCHARIDES
NUCLEI
NUCLEOTIDES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANOIDS
ORGANS
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
POLYMERIZATION
PROTEINS
RADIOISOTOPES
SACCHARIDES
SECRETION
TOXIC MATERIALS
TOXINS
TRACER TECHNIQUES