Unraveling the CLCC1 interactome: Impact of the Asp25Glu variant and its interaction with SigmaR1 at the Mitochondrial-Associated ER Membrane (MAM)

Ilaria D'Atri, Emily Rose Martin, Liming Yang, Elizabeth Sears, Emma Baple, Andrew H. Crosby, John K. Chilton, Asami Oguro-Ando*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Downloads (Pure)

Abstract

The endoplasmic reticulum (ER) plays an indispensable role in cellular processes, including maintenance of calcium homeostasis, and protein folding, synthesized and processing. Disruptions in these processes leading to ER stress and the accumulation of misfolded proteins can instigate the unfolded protein response (UPR), culminating in either restoration of balanced proteostasis or apoptosis. A key player in this intricate balance is CLCC1, an ER-resident chloride channel, whose essential role extends to retinal development, regulation of ER stress, and UPR. The importance of CLCC1 is further underscored by its interaction with proteins localized to mitochondria-associated endoplasmic reticulum membranes (MAMs), where it participates in UPR induction by MAM proteins. In previous research, we identified a p.(Asp25Glu) pathogenic CLCC1 variant associated with retinitis pigmentosa (RP) (CLCC1 hg38 NC_000001.11; NM_001048210.3, c.75C > A; UniprotKB Q96S66). In attempt to decipher the impact of this variant function, we leveraged liquid chromatography-mass spectrometry (LC-MS) to identify likely CLCC1-interacting proteins. We discovered that the CLCC1 interactome is substantially composed of proteins that localize to ER compartments and that the Asp25Glu variant results in noticeable loss and gain of specific protein interactors. Intriguingly, the analysis suggests that the CLCC1Asp25Glu mutant protein exhibits a propensity for increased interactions with cytoplasmic proteins compared to its wild-type counterpart. To corroborate our LC-MS data, we further scrutinized two novel CLCC1 interactors, Calnexin and SigmaR1, chaperone proteins that localize to the ER and MAMs. Through microscopy, we demonstrate that CLCC1 co-localizes with both proteins, thereby validating our initial findings. Moreover, our results reveal that CLCC1 co-localizes with SigmaR1 not merely at the ER, but also at MAMs. These findings reinforce the notion of CLCC1 interacting with MAM proteins at the ER-mitochondria interface, setting the stage for further exploration into how these interactions impact ER or mitochondria function and lead to retinal degenerative disease when impaired.

Original languageEnglish
Article number137778
JournalNeuroscience Letters
Volume830
DOIs
Publication statusPublished - 1 May 2024

ASJC Scopus subject areas

  • General Neuroscience

Keywords

  • CLCC1
  • Endoplasmic reticulum
  • MAM
  • Retinitis pigmentosa
  • SigmaR1

Fingerprint

Dive into the research topics of 'Unraveling the CLCC1 interactome: Impact of the Asp25Glu variant and its interaction with SigmaR1 at the Mitochondrial-Associated ER Membrane (MAM)'. Together they form a unique fingerprint.

Cite this