Human platelet glycoprotein V: a surface leucine-rich glycoprotein related to adhesion.
Human platelet glycoprotein V (Mr 82,000) is a surface glycoprotein and a substrate for thrombin, undergoing proteolytic cleavage by thrombin and releasing a soluble fragment, glycoprotein Vfl (Mr 69,000). It does not appear to be the receptor for thrombin's agonist effect on platelets. A congenital platelet disorder, Bernard-Soulier syndrome, is marked by a deficiency of glycoprotein V and two other surface glycoproteins, Ib-IX. The latter two, Ib-IX, constitute the platelet receptor for von Willebrand factor, mediate arterial platelet adhesion, and contain unique 24-amino acid sequences, termed "leucine-rich glycoprotein" segments. The segments relate to adhesive function and distinguish the leucine-rich glycoprotein family. Surface glycoprotein V is not physically associated with Ib-IX nor does it bind to von Willebrand factor. To date, no common denominator has been found that explains the combined deficiency of glycoproteins V and Ib-IX in Bernard-Soulier syndrome. This study describes the isolation of glycoprotein V/anti-glycoprotein V antibody and the analysis of three glycoprotein V peptides that contain "leucine-rich" sequences. Therefore, glycoprotein V shares the "leucine-rich" structure with platelet glycoproteins Ib-IX and belongs to the family of leucine-rich glycoproteins.
Roth
G J
GJ
Hematology Section, Veterans Administration Medical Center, Seattle, Washington 98108.
Church
T A
TA
McMullen
B A
BA
Williams
S A
SA
D000595:Amino Acid Sequence; D006801:Humans; D008969:Molecular Sequence Data; D010973:Platelet Adhesiveness; D010980:Platelet Membrane Glycoproteins / Q000032:analysis / Q000276:immunology / Q000302:isolation & purification*
D010980:Platelet Membrane Glycoproteins