Regulatory function of the C-terminal segment of guanylate cyclase-activating protein 2статья
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Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 11 ноября 2015 г.
Авторы:
Zernii E.Y. ,
Grigoriev I.I. ,
Nazipova A.A. ,
Scholten A. ,
Kolpakova T.V. ,
Zinchenko D.V. ,
Kazakov A.S. ,
Senin I.I. ,
Permyakov S.E. ,
Dell’Orco D. ,
Philippov P.P. ,
Koch K.W.
Журнал:
Biochimica et Biophysica Acta - Proteins and Proteomics
Том:
1854
Номер:
10
Год издания:
2015
Издательство:
Elsevier BV
Местоположение издательства:
Netherlands
Первая страница:
1325
Последняя страница:
1337
DOI:
10.1016/j.bbapap.2015.05.005
Аннотация:
Neuronal responses to Ca2 +-signals are provided by EF-hand-type neuronal Ca2 +-sensor (NCS) proteins, which have similar core domains containing Ca2 +-binding and target-recognizing sites. NCS proteins vary in functional specificity, probably depending on the structure and conformation of their non-conserved C-terminal segments. Here, we investigated the role of the C-terminal segment in guanylate cyclase activating protein-2, GCAP2, an NCS protein controlling the Ca2 +-dependent regulation of photoreceptor guanylate cyclases. We obtained two chimeric proteins by exchanging C-terminal segments between GCAP2 and its photoreceptor homolog recoverin, a Ca2 +-sensor controlling rhodopsin kinase (RK) activity. The exchange affected neither the structural integrity of GCAP2 and recoverin nor the Ca2 +-sensitivity of GCAP2. Intrinsic fluorescence, circular dichroism, biochemical studies and hydrophobic dye probing revealed Ca2 +-dependent conformational transition of the C-terminal segment of GCAP2 occurring in the molecular environment of both proteins. In Ca2 +-GCAP2, the C-terminal segment was constrained and its replacement provided the protein with approximately two-fold inhibitory activity towards RK, suggesting that the segment contributes to specific target recognition by interfering with RK-binding. Upon Ca2 +-release, it became less constrained and more available for phosphorylation by cyclic nucleotide-dependent protein kinase. The transition from the Ca2 +-bound to the apo-state exposed hydrophobic sites in GCAP2, and was associated with its activating function without affecting its dimerization. The released C-terminal segment participated further in photoreceptor membrane binding making it sensitive to phosphorylation. Thus, the C-terminal segment in GCAP2 confers target selectivity, facilitates membrane binding and provides sensitivity of the membrane localization of the protein to phosphorylation by signaling kinases.
© 2015 Elsevier B.V.
Добавил в систему:
Зерний Евгений Юрьевич