Opposing roles of E3 ligases TRIM23 and TRIM21 in regulation of ion channel ANO1 protein levels.

ANO1 (TMEM16A) is a calcium-activated chloride channel that plays critical roles in diverse physiological processes, such as sensory transduction and epithelial secretion. ANO1 levels have been shown to be altered under physiological and pathological conditions, although the molecular mechanisms that control ANO1 protein levels remain unclear. The ubiquitin-proteasome system is known to regulate the levels of numerous ion channels, but little information is available regarding whether and how ubiquitination regulates levels of ANO1. Here, we showed that two E3 ligases, TRIM23 and TRIM21, physically interact with the C-terminus of ANO1. In vitro and in vivo assays demonstrated that whereas TRIM23 ubiquitinated ANO1 leading to its stabilization, TRIM21 ubiquitinated ANO1 and induced its degradation. Notably, ANO1 regulation by TRIM23 and TRIM21 is involved in chemical-induced pain sensation, salivary secretion, and heart-rate control in mice, and TRIM23 also mediates ANO1 upregulation induced by epidermal growth factor (EGF) treatment. Our results suggest that these two antagonistic E3 ligases act together to control ANO1 expression and function. Our findings reveal a previously unrecognized mechanism for regulating ANO1 protein levels and identify a potential molecular link between ANO1 regulation, EGF, and other signaling pathways. Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.

Citation

Xu Cao, Zijing Zhou, Ye Tian, Zhengzhao Liu, Kar On Cheng, Xibing Chen, Wenbao Hu, Yuk Ming Wong, Xiaofen Li, Hailin Zhang, Ronggui Hu, Pingbo Huang. Opposing roles of E3 ligases TRIM23 and TRIM21 in regulation of ion channel ANO1 protein levels. The Journal of biological chemistry. 2021 May 03:100738

PMID: 33957127

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