The muscle-specific intermediate filament scaffold protein desmin has been a focal point in the quest to understand cardiomyopathies and heart failure. Myocardial deficiencies displayed by desmin-mutant mice have been linked to malfunction of mitochondria, and similar abnormalities are seen with mutations in the small abundant heat shock protein αB-crystallin. Therefore, Yassemi Capetanaki and colleagues now (p. 3705) address the potential interplay between desmin and αB-crystallin. The authors overexpressed αB-crystallin in desmin^−/− mice, which, strikingly, rescues the ultrastructural defects of cardiomyocytes and, moreover, restores changes in mitochondrial protein levels that were due to desmin deficiency. Overall, desmin^−/− animals that overexpressed αB-crystallin had improved cardiac function and could survive an obligatory swimming exercise, in contrast to desmin^−/− mice. Further, the abnormal activation of the mitochondrial permeability transition pore and dissipation of mitochondrial membrane potential, which are observed in the desmin^−/− mice, are inhibited by αB-crystallin overexpression. In addition, the authors show that both desmin and αB-crystallin localise at sarcoplasmic-reticulum–mitochondria-associated membranes, and interact with the voltage-dependent anion channel (VDAC), ATP synthase and Mic60, a core component of the mitochondrial contact site and cristae organising system (MICOS). Together, these new data provide insight into the mitochondrial and cardioprotective role of αB-crystallin and desmin.

• © 2016. Published by The Company of Biologists Ltd