Functions of the extracellular histidine residues of receptor activity-modifying proteins vary within adrenomedullin receptors
Functions of the extracellular histidine residues of receptor activity-modifying proteins vary within adrenomedullin receptors
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DOI：
10.1016/j.bbrc.2008.09.105
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发表时间：
2008-12-05
影响因子：
3.1
通讯作者：
Kato, Johji
中科院分区：
文献类型：
--
作者：
Kuwasako, Kenji;Kitamura, Kazuo;Kato, Johji
受体活性修饰蛋白(RAMP)-2和-3分子伴侣降钙素受体样受体(CRLR)结合到质膜，在那里它们共同形成异二聚体肾上腺髓质素(AM)受体。我们通过在HEK-293细胞中共表达hCRLR和V5标记的hRAMP2或-3突变体，研究了位于RAMP胞外区的His残基在AM受体转运和受体信号转导中的作用。流式细胞仪分析显示，hRAMP2-H71a介导了正常的hCRLR表面递送，但所产生的异源二聚体显著减少了[I-125]AM结合和AM诱导的cAMP产生。HRAMP2-H124A和-H127A的表达影响hCRLR的表面传递，从而损害或取消AM结合和受体信号转导。虽然hRAMP3-H97A介导了hCRLR的完全表面传递，但所产生的异源二聚体显示AM结合和信号转导受损。其他His残基提出上诉，与hCRLR相关功能无关。因此，hRAMP2和-3的组氨酸残基对AM受体的功能起不同的调控作用。(C)2008 Elsevier Inc.保留所有权利。
Receptor activity-modifying protein (RAMP)-2 and -3 chaperone calcitonin receptor-like receptor (CRLR) to the plasma membrane, where together they form heterodimeric adrenomedullin (AM) receptors. We investigated the contributions made by His residues situated in the RAMP extracellular domain to AM receptor trafficking and receptor signaling by co-expressing hCRLR and V5-tagged-hRAMP2 or -3 mutants in which a His residue was substituted with Ala in HEK-293 cells. Flow cytometric analysis revealed that hRAMP2-H71A mediated normal hCRLR surface delivery, but the resultant heterodimers showed significantly diminished [I-125]AM binding and AM-evoked cAMP production. Expression of hRAMP2-H124A and -H127A impaired Surface delivery of hCRLR, which impaired or abolishing AM binding and receptor signaling. Although hRAMP3-H97A mediated full surface delivery of hCRLR, the resultant heterodimers showed impaired AM binding and signaling. Other His residues appealed uninvolved in hCRLR-related functions. Thus, the His residues of hRAMP2 and -3 differentially govern AM receptor function. (C) 2008 Elsevier Inc. All rights reserved.