C‐terminal amino acid determination of the transmembrane subunits of the human platelet fibrinogen receptor, the GPIIb/IIIa complex

FEBS Letters

Gonzalez-Rodriguez, J.²  Schäfer, W.¹  Henscher, A.¹  Calvete, J.J.¹ 

[1] Max-Planck-Institut für Biochemie, 8033 Martinsried, FRG;Instituto de Quimica-Fisica, CSIC, c/Serrano, 119, 28006 Madrid, Spain

关键词: Platelet;    GPIIb/IIIa;    C-terminal sequencing;    Mass spectrometry;    Posttranslational modification;    GPIIb;    glycoprotein IIb;    GPIIIa;    glycoprotein Ilia;    CM-GPIIIa;    CM-GPIIbβ;    fully reduced and carboxymethylated glycoprotein IIIa and IIbβ respectively;    HEL human erythroleukemic cell line;   

DOI  :  10.1016/0014-5793(90)80701-J

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Glycoproteins IIb (GPIIb) and IIIa (GPIIIa) form the Ca²⁺ -dependent GPIIb/IIIa complex, which acts as the fibrinogen receptor on activated platelets. GPIIb and GPIIIa are synthesized as single peptide chains. The GPIIb precursor is processed proteolytically to yield two disulphide-bonded chains, GPIIba and GPIIbß. The GPIIb/IIIa complex has two membrane attachment sites located at the C-tennini ofGPIIß and GPIIIa. The short cytoplasmic tails of GPIIbß and/or GPIIIa become most likely associated to the cytoskeleton of activated platelets. In the present work the C-tenninal amino acid residues of platelet GPIIbß and GPIIIa have been analyzed by protein-chemical methods and compared with those predicted from cDNA analysis. We were able to confirm the positions of the C-tennini in both glycoproteins and the identity of the C-tenninus predicted for GPIIIa, i.e. threonine. However, glutamine, not glutamic acid as predicted for GPIIbß from the human erythroleukemic cell line and megakaryocyte cells, was found to be the C-terminal amino acid of GPIIß. This indicates that the glutamic arid in the GPIIb precursor is posttranslationally modified to glutamine.

【 授权许可】

Unknown