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）肌肉肌质网（SR）的钙释放通道（CRC）/ryanodine受体是伴有结构配方（Ryanodine受体（RYR）1受体）II D24 D2（FKBPP12）II D24 D24 D2和（Ryanodine受体（RYR）1受体）和（Ryanodine受体（RYR）1受体）和（Ryanodine受体（RYR）1受体）和（Ryanodine受体（RYR）1受体）的杂音组合复合物（SR）。（FKBP12.6）II D24 D2，其中FKBP12和FKBP12.6是免疫抑制药物FK506的12 kDa受体的同工型。使用D135E D1S标记的FKBP12和D135E D1S标记的FKBP12.6作为研究与CRC相互作用的问题，我们发现：1）类似于其在骨骼肌中的作用，类似于其在骨骼肌中的作用。 2）两种FKBP同工型都与FKBP分裂的SKMSR结合，并与SKMSR的内生结合的FKBP12交换； 3）相比之下，仅FKBP12.6与内生结合的FKBP12.6交换或与FKBP分裂的CSR进行重新固定。这种选择性结合似乎解释了为什么心脏CRC被分离为具有FKBP12.6的复合物，而骨骼肌CRC被分离为具有FKBP12.6的复合物，尽管仅在两种肌肉类型的肌周中都能检测到FKBP12。与通过从骨骼肌中去除FKBP激活通道的激活相反，在FKBP分裂的CSR中，CRC活性未检测到激活。 FKBP的这种递延作用可能反映出心脏与骨骼肌的兴奋征收耦合的调节的基本差异。我们还检查了FKBP是否通过免疫定位研究与RYR相关。在大鼠骨骼肌截面中，将RYR和FKBP均视为横向带，并沿着肌肉纤维的全长周期性进行周期性。当相同的部分用抗ryr和抗FKBP抗体双重转化时，FKBP的带叠加在RYR的带上。这些结果表明，FKBP与RYR原位有关，并调节RYR/CRC在骨骼肌中的功能。