Cobb T, Hwang I, Soukar M, Namkoong S, Cho US, Safdar M, Kim M, Wessells RJ, Lee JH.
Iditarod, a
Drosophila homolog of the Irisin precursor
FNDC5, is critical for exercise performance and cardiac autophagy.
Proc Natl Acad Sci U S A 2023;
120:e2220556120. [PMID:
37722048 PMCID:
PMC10523451 DOI:
10.1073/pnas.2220556120]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 07/28/2023] [Indexed: 09/20/2023] Open
Abstract
Mammalian FNDC5 encodes a protein precursor of Irisin, which is important for exercise-dependent regulation of whole-body metabolism. In a genetic screen in Drosophila, we identified Iditarod (Idit), which shows substantial protein homology to mouse and human FNDC5, as a regulator of autophagy acting downstream of Atg1/Atg13. Physiologically, Idit-deficient flies showed reduced exercise performance and defective cold resistance, which were rescued by exogenous expression of Idit. Exercise training increased endurance in wild-type flies, but not in Idit-deficient flies. Conversely, Idit is induced upon exercise training, and transgenic expression of Idit in wild-type flies increased endurance to the level of exercise trained flies. Finally, Idit deficiency prevented both exercise-induced increase in cardiac Atg8 and exercise-induced cardiac stress resistance, suggesting that cardiac autophagy may be an additional mechanism by which Idit is involved in the adaptive response to exercise. Our work suggests an ancient role of an Iditarod/Irisin/FNDC5 family of proteins in autophagy, exercise physiology, and cold adaptation, conserved throughout metazoan species.
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