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

Conference · Fri May 01 00:00:00 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-; TRN: 87-037102
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 46:6; Conference: 78. annual meeting of the American Society of Biological Chemists conference, Philadelphia, PA, USA, 7 Jun 1987
• Country of Publication: United States
• Language: English

Related Subjects

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