Regulatory function of the C-terminal segment of guanylate cyclase-activating protein 2

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.

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

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Regulatory function of the C-terminal segment of guanylate cyclase-activating protein 2статья