Mitochondrial OPA1 cleavage is reversibly activated by differentiation of H9c2 cardiomyoblasts.

Optic atrophy-1 (OPA1) is a dynamin-like GTPase localized to the mitochondrial inner membrane, playing key roles in inner membrane fusion and cristae maintenance. OPA1 is regulated by the mitochondrial transmembrane potential (Δψm): when Δψm is intact, long OPA1 isoforms (L-OPA1) carry out inner membrane fusion. Upon loss of Δψm, L-OPA1 isoforms are proteolytically cleaved to short (S-OPA1) isoforms by the stress-inducible OMA1 metalloprotease, causing collapse of the mitochondrial network and promoting apoptosis. Here, we show that L-OPA1 isoforms of H9c2 cardiomyoblasts are retained under loss of Δψm, despite the presence of OMA1. However, when H9c2s are differentiated to a more cardiac-like phenotype via treatment with retinoic acid (RA) in low serum media, loss of Δ ψm induces robust, and reversible, cleavage of L-OPA1 and subsequent OMA1 degradation. These findings indicate that a potent developmental switch regulates Δ ψm-sensitive OPA1 cleavage, suggesting novel developmental and regulatory mechanisms for OPA1 homeostasis. Copyright © 2020 The Author(s). Published by Elsevier B.V. All rights reserved.

Citation

Iraselia Garcia, Fredy Calderon, Patrick De la Torre, Shaynah St Vallier, Cristobal Rodriguez, Divya Agarwala, Megan Keniry, Wendy Innis-Whitehouse, Robert Gilkerson. Mitochondrial OPA1 cleavage is reversibly activated by differentiation of H9c2 cardiomyoblasts. Mitochondrion. 2021 Mar;57:88-96

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PMID: 33383158

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