Phosphorylation of phosphoinositides in human platelets
32P-labelling of phosphatidylinositol (PI), PI-4-monophosphate (PIP), PI-4,5-bisphosphate (PIP2) and phosphatidic acid (PA) in /sup 32/P-labelled intact human platelets was investigated in the presence of various agents which alter intracellular level of cAMP or Ca/sup 2 +/. Addition of dibutyryl cAMP to intact platelets pre- or pulse labelled with /sup 32/P resulted in increased /sup 32/P-labelling of PIP and in concomitant decreased /sup 32/P-labelling of PI without affecting that of PIP2 or PA. Similar changes were observed in intact platelets treated by prostaglandin I2 (PGI2) or a new low Km phosphodiesterase inhibitor (DN-9693). When intracellular Ca/sup 2 +/ was chelated by loading quin 2-AM to intact platelets, /sup 32/P-labelling of PIP was significantly increased in a dose related manner. From these observations it was concluded that PI kinase is activated by elevation of cAMP or chelation of Ca/sup 2 +/ in intact platelets.
- Research Organization:
- Osaka Univ. Medical School, Japan
- OSTI ID:
- 6937303
- Journal Information:
- Thromb. Res.; (United States), Journal Name: Thromb. Res.; (United States) Vol. 2; ISSN THBRA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ALKALINE EARTH METALS
AMP
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BIOLOGY
BLOOD
BLOOD CELLS
BLOOD PLATELETS
BODY FLUIDS
CALCIUM
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
ELEMENTS
ENZYME ACTIVITY
ENZYMES
ESTERS
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
LABELLING
LIGHT NUCLEI
LIPIDS
MATERIALS
METALS
NUCLEI
NUCLEOTIDES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PHOSPHOLIPIDS
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
PHOSPHORUS-GROUP TRANSFERASES
PHOSPHORYLATION
PHOSPHOTRANSFERASES
PROSTAGLANDINS
RADIOBIOLOGY
RADIOISOTOPES
TRACER TECHNIQUES
TRANSFERASES