The human disease geneCLEC16Aencodes an intrinsically disordered protein region required for mitochondrial quality control

Abstract

CLEC16A regulates mitochondrial health through mitophagy and is associated with over 20 human diseases. While CLEC16A has ubiquitin ligase activity, the key structural and functional regions of CLEC16A, and their relevance for human disease, remain unknown. Here, we report that a disease-associated CLEC16A variant lacks a C-terminal intrinsically disordered protein region (IDPR) that is critical for mitochondrial quality control. Using carbon detect NMR, we find that the CLEC16A C terminus lacks secondary structure, validating the presence of an IDPR. Loss of the CLEC16A C-terminal IDPR in vivo impairs pancreatic β-cell mitophagy, mitochondrial function, and glucose-stimulated insulin secretion, ultimately causing glucose intolerance. Deletion of the CLEC16A C-terminal IDPR increases its self-ubiquitination and destabilizes CLEC16A, thus impairing formation of a critical CLEC16A-dependent mitophagy complex. Importantly, CLEC16A stability is dependent on proline bias within the C-terminal IDPR, but not amino acid sequence order or charge. Together, we clarify how an IDPR in CLEC16A prevents diabetes, thus implicating the disruption of IDPRs as novel pathological contributors to diabetes and other CLEC16A-associated diseases.

CLEC16A interacts with retromer and TRIM27, and its loss impairs endosomal trafficking and neurodevelopment

“…This plasmid produces a CLEC16A protein lacking the C-terminal domain (Δ19 pEGFP-CLEC16A). The C-terminal domain includes a part of the putative intrinsically disordered region (IDR), but no other annotated protein domains (Gingerich et al 2021). Overexpression of Δ19 pEGFP-CLEC16A showed synthesis of a mutant protein with a diffuse GFP signal throughout the cytoplasm, but complete loss of the early endosomal localization (Fig.…”