Specific interaction of FK506 binding protein (FKBP) isoforms with the ryanodine/CaィイD12+ィエD1 release channel subtypes

FK506 结合蛋白 (FKBP) 亚型与兰尼定/CaD12+D1 释放通道亚型的特异性相互作用

基本信息

批准号：
10470024
负责人：
ITO Yushi
金额：
$ 8.06万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

The calcium release channels (CRC)/ryanodine receptor of skeletal (Sk) and (C) muscle sarcoplasmic reticulum (SR) are hetero-oligomeric complexes with the structural formulas (ryanodine receptor(RYR)1 receptor)ィイD24ィエD2 (FKBP12)ィイD24ィエD2 and (RYP2 protomer)ィイD24ィエD2 (FKBP12.6)ィイD24ィエD2, respectively, where FKBP12 and FKBP12.6 are isoforms of the 12-kDa receptor for the immunosuppressant drug FK506. Using ィイD135ィエD1S-labeled FKBP12 and ィイD135ィエD1S-labeled FKBP12.6 as probes to study the interaction with CRC, we find that : 1) analogous to its action in skeletal muscle sarcoplasmic reticulum (SkMSR), FK506 dissociates FKBP12.6 from CSR ; 2) both FKBP isoforms bind to FKBP-stripped SkMSR and exchange with endogenously bound FKBP12 of SkMSR ; and 3) by contrast, only FKBP12.6 exchanges with endogenously bound FKBP12.6 or rebinds to FKBP-stripped CSR. This selective binding appears to explain why the cardiac CRC is isolated as a complex with FKBP12.6, whereas the skeletal muscle CRC is isolated as a complex with FKBP12.6 although only FKBP12 is detectable in the myoplasm of both muscle types. In contrast to the activation of the channel by removal of FKBP from skeletal muscle, no activation is detected in CRC activity in FKBP-stripped CSR. This deferential action of FKBP may reflect a fundamental difference in the modulation of excitation-contraction coupling in heart versus skeletal muscle.we also examined whether FKBP is associated with the RYR in situ by immunolocalization studies. In rat skeletal muscle section, both the RYR and FKBP were detected as transverse bands with periodicity along the full length of the muscle fiber. When the same section was dual-proved with anti-RYR and anti-FKBP antibody, the bands of FKBP superimposed upon the bands of the RYR. These results suggest that FKBP is associated with the RYR in situ and modulates the function of the RYR/CRC in skeletal muscle.

骨骼 (Sk) 和 (C) 肌肉肌浆网 (SR) 的钙释放通道 (CRC)/兰尼碱受体是异源寡聚复合物，其结构式为 (兰尼碱受体 (RYR)1 受体) FKBP12) D24 D2 和 (RYP2)原体）D24 D2 (FKBP12.6)D24D2，其中FKBP12和FKBP12.6是免疫抑制剂药物FK506的12-kDa受体的亚型，使用D1S标记的FKBP12和D135 D1S标记的FKBP12.6作为探针来研究与CRC的相互作用。 ,我们发现：1) 类似于其在骨骼肌肌浆网 (SkMSR) 中的作用，FK506 将 FKBP12.6 从 CSR 上解离；2) 两种 FKBP 亚型均与 FKBP 剥离的 SkMSR 结合，并与 SkMSR 的内源性结合的 FKBP12 进行交换；相比之下，只有 FKBP12.6 与内源结合的交换FKBP12.6 或与 FKBP 剥离的 CSR 重新结合，这种选择性结合似乎解释了为什么心脏 CRC 被分离为与 FKBP12.6 的复合物，而骨骼肌 CRC 被分离为与 FKBP12.6 的复合物，尽管仅可检测到 FKBP12。与通过从骨骼肌去除 FKBP 来激活通道相反，在 CRC 活性中未检测到激活。 FKBP 剥离的 CSR 中 FKBP 的这种防御作用可能反映了心脏与骨骼肌中兴奋-收缩耦合调节的根本差异。我们还通过大鼠骨骼肌中的免疫定位研究检查了 FKBP 是否与原位 RYR 相关。当用抗 RYR 和 FKBP 双重证明同一切片时，RYR 和 FKBP 均检测为沿肌纤维全长具有周期性的横向带。抗 FKBP 抗体，FKBP 的条带叠加在 RYR 的条带上。这些结果表明 FKBP 与 RYR 原位相关，并调节骨骼肌中 RYR/CRC 的功能。