Department of Internal Medicine and Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, MI, USA.
Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI, USA.
Autophagy. 2023 Feb;19(2):525-543. doi: 10.1080/15548627.2022.2080383. Epub 2022 May 30.
CLEC16A regulates mitochondrial health through mitophagy and is associated with over 20 human diseases. However, 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. IDPRs comprise nearly half of the human proteome, yet their mechanistic roles in human disease are poorly understood. 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 impairs mitophagy, mitochondrial function, and glucose-stimulated insulin secretion, ultimately causing glucose intolerance. Deletion of the CLEC16A C-terminal IDPR increases CLEC16A ubiquitination and degradation, thus impairing assembly of the mitophagy regulatory machinery. Importantly, CLEC16A stability is dependent on proline bias within the C-terminal IDPR, but not amino acid sequence order or charge. Together, we elucidate how an IDPR in CLEC16A regulates mitophagy and implicate pathogenic human gene variants that disrupt IDPRs as novel contributors to diabetes and other CLEC16A-associated diseases. CAS: carbon-detect amino-acid specific; IDPR: intrinsically disordered protein region; MEFs: mouse embryonic fibroblasts; NMR: nuclear magnetic resonance.
CLEC16A 通过自噬来调节线粒体健康，与 20 多种人类疾病有关。然而，CLEC16A 的关键结构和功能区域及其与人类疾病的相关性仍不清楚。在这里，我们报告一种与疾病相关的 CLEC16A 变体缺乏一个对线粒体质量控制至关重要的 C 端无规卷曲蛋白区域（IDPR）。IDPRs 几乎占人类蛋白质组的一半，但它们在人类疾病中的作用机制仍知之甚少。使用碳探测 NMR，我们发现 CLEC16A 的 C 端没有二级结构，验证了 IDPR 的存在。CLEC16A C 端 IDPR 的缺失会损害自噬、线粒体功能和葡萄糖刺激的胰岛素分泌，最终导致葡萄糖不耐受。删除 CLEC16A C 端 IDPR 会增加 CLEC16A 的泛素化和降解，从而损害自噬调节机制的组装。重要的是，CLEC16A 的稳定性取决于 C 端 IDPR 中的脯氨酸偏好，而不是氨基酸序列顺序或电荷。总之，我们阐明了 CLEC16A 中的 IDPR 如何调节自噬，并暗示破坏 IDPR 的致病性人类基因突变是糖尿病和其他 CLEC16A 相关疾病的新发病机制。CAS：碳探测氨基酸特异；IDPR：无规卷曲蛋白区；MEFs：小鼠胚胎成纤维细胞；NMR：核磁共振。
