The phosphorylation of the two‐chain form of vitronectin by protein kinase A is heparin dependent

FEBS Letters

Korc-Grodzicki, Beatriz¹  Kreizman, Tamar¹  Chain, Daniel¹  Shaltiel, Shmuel¹ 

[1] Department of Chemical Immunology, The Weizmann Institute of Science, Rehovot, 76100, Israel

关键词: Conformational change;    Hemostasis;    Heparin;    Platelet;    Protein kinase A;    Vitronectin;    GAG;    glycosaminoglycan;    Hepes;    N-2-hydroxyethyl piperazine-N' -2-ethanesulfonic acid;    Mes;    2-(N-morpholino)-ethanesulfonic acid;    PKA;    protein kinase A;    R;    reducing conditions;    NR;    non-reducing conditions;    SDS-PAGE;    polyacrylamide gel electrophoresis in the presence of sodium dodecylsulfate;    V75;    the one chain form of vitronectin;    V65 +10;    the two-chain form of vitronectin;   

DOI  :  10.1016/0014-5793(90)81159-L

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

In circulating blood, vitronectin occurs in two forms: a single-chain (75 kDa) and an endogenously clipped two-chain form (65 kDa and 10 kDa) held together by a disulfide bridge. The 75 kDa form was previously shown to be phosphorylated at Ser³⁷⁸ by protein kinase A, released by physiologically stimulated platelets. By contrast, at pH 7.5 the two-chain form is not phosphorylated at all. Heparin or heparan sulfate are shown here to modulate the conformation of clipped vitronectin at physiological pH, exposing Ser³⁷⁸ and allowing its stoichiometric phosphorylation by the kinase. At this pH the two-chain form of vitronectin in plasma exhibits a higher affinity for heparin, and behaves as a flexible molecule, which can conformationally respond to heparin and heparan sulfate, effectors involved in vitronectin function.

【 授权许可】

Unknown