Human platelet glycoprotein Ia. One component is only expressed on the surface of activated platelets and may be a granule constituent

Journal Article · Thu Jan 05 04:00:00 EST 1989 · J. Biol. Chem.; (United States)

OSTI ID:6569560

Bienz, D; Clemetson, K J

Glycoprotein Ia (GP Ia) is a relatively minor component of human blood platelets thought to be a receptor involved in collagen-induced platelet activation. However, some difficulties exist with the definition of this glycoprotein. The expression of GP Ia on resting (prostacyclin analogue-treated) and thrombin-activated platelets was compared by surface labeling with /sup 125/I-lactoperoxidase. Intact platelets or platelets solubilized in sodium dodecyl sulfate were labeled with periodate/(/sup 3/H)NaBH/sub 4/. Analysis on two-dimensional isoelectric focusing/sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels showed that GP Ia is very poorly labeled in resting platelets. After activation a new spot (GP Ia*) appears with the same relative molecular mass as GP Ia under reducing conditions. GP Ia and Ia* can be clearly separated by two-dimensional nonreduced/reduced gel electrophoresis. Therefore, two glycoproteins which have been termed GP Ia exist in platelets with similar molecular weight and pI under reducing conditions. One of these (GP Ia*) is only surface-labeled when platelets are activated, indicating that it is only exposed on the surface of activated platelets. Supernatant from activated platelets contains this glycoprotein as well as other granule components. This glycoprotein is missing in platelets from two patients with collagen-response defects.

• Research Organization: Univ. of Berne (Switzerland)
• OSTI ID: 6569560
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 264:1; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BLOOD COAGULATION
BLOOD PLATELETS
BODY FLUIDS
CARBOHYDRATES
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ELECTROPHORESIS
ENZYMES
GLUCOPROTEINS
GLYCOPROTEINS
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
LABELLED COMPOUNDS
LABELLING
MAMMALS
MAN
MATERIALS
MEMBRANE PROTEINS
MOLECULAR WEIGHT
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
OXIDOREDUCTASES
OXYGEN COMPOUNDS
PEROXIDASES
PRIMATES
PROTEINS
RADIOISOTOPES
SACCHARIDES
SULFATES
SULFUR COMPOUNDS
TRITIUM COMPOUNDS
VERTEBRATES