Regulation of clc-2 chloride channel proteostasis by molecular chaperones: Correction of leukodystrophy-associated defect

Ssu Ju Fu, Meng Chun Hu, Cheng Tsung Hsiao, An Ting Cheng, Tsung Yu Chen, Chung Jiuan Jeng, Chih Yung Tang

Research output: Contribution to journalArticlepeer-review

Abstract

The ClC-2 channel plays a critical role in maintaining ion homeostasis in the brain and the testis. Loss-of-function mutations in the ClC-2-encoding human CLCN2 gene are linked to the white matter disease leukodystrophy. Clcn2-deficient mice display neuronal myelin vacuolation and testicular degeneration. Leukodystrophy-causing ClC-2 mutant channels are associated with anomalous proteostasis manifesting enhanced endoplasmic reticulum (ER)-associated degradation. The molecular nature of the ER quality control system for ClC-2 protein remains elusive. In mouse testicular tissues and Leydig cells, we demonstrated that endogenous ClC-2 co-existed in the same protein complex with the molecular chaperones heat shock protein 90β (Hsp90β) and heat shock cognate protein (Hsc70), as well as the associated co-chaperones Hsp70/Hsp90 organizing protein (HOP), activator of Hsp90 ATPase homolog 1 (Aha1), and FK506-binding protein 8 (FKBP8). Further biochemical analyses revealed that the Hsp90β-Hsc70 chaperone/co-chaperone system pro-moted mouse and human ClC-2 protein biogenesis. FKBP8 additionally facilitated membrane trafficking of ClC-2 channels. Interestingly, treatment with the Hsp90-targeting small molecule 17-allylamino-17-demethoxygeldanamycin (17-AAG) substantially boosted ClC-2 protein expres-sion. Also, 17-AAG effectively increased both total and cell surface protein levels of leukodystro-phy-causing loss-of-function ClC-2 mutant channels. Our findings highlight the therapeutic potential of 17-AAG in correcting anomalous ClC-2 proteostasis associated with leukodystrophy.

Original languageEnglish (US)
Article number5859
JournalInternational journal of molecular sciences
Volume22
Issue number11
DOIs
StatePublished - Jun 1 2021

Keywords

  • 17-AAG
  • Channelopathy
  • Chaperone
  • Co-chaperone
  • Protein quality control
  • Proteostasis

ASJC Scopus subject areas

  • Catalysis
  • Molecular Biology
  • Spectroscopy
  • Computer Science Applications
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

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