bims-mitpro 2026-07-05 papers

Issue of 2026–07–05
three papers selected by
Andreas Kohler, Umeå University

Front Physiol. 2026 ;17 1873221

When mitochondria lose their fold: matrix proteostasis and stress signaling.

A dedicated network of chaperones and proteases is present in the mitochondrial matrix that orchestrates import, folding, disaggregation and eventually degradation of proteins. When this network is overwhelmed, unfolded or misfolded proteins accumulate in different types of aggregates which may either support recovery of functional proteins, initiate spatial sequestration or drive toxic aggregation. Here, we discuss mitochondrial protein aggregation and how mitochondrial proteostasis stress is communicated to the rest of the cell.

Keywords: Hsp70; mitochondria; mitochondria-nuclear signaling; protein aggregation; proteostasis

DOI: https://doi.org/10.3389/fphys.2026.1873221

J Biochem. 2026 Jun 30. pii: mvag048. [Epub ahead of print]

BNIP3/NIX-dependent mitophagy: molecular mechanisms and physiological roles.

Tamara Ginevskaia, Takayuki Mito, Keiichi Inoue, Tomotake Kanki.

Mitochondria are essential for cellular metabolism and homeostasis, and their quality and quantity must therefore be tightly controlled. Mitophagy, a selective form of autophagy targeting mitochondria, contributes to this control by eliminating damaged or superfluous mitochondria. Among the known mitophagy pathways, BNIP3/NIX-dependent mitophagy has emerged as a key mechanism, particularly under hypoxic and metabolic stress. Recent studies have provided important insights into how BNIP3 and NIX are transcriptionally induced, post-translationally regulated, and functionally coupled to the core autophagy machinery. These studies have also clarified their roles in isolation membrane tethering, membrane elongation, and mitophagosome formation. Beyond its molecular basis, accumulating evidence indicates that BNIP3/NIX-dependent mitophagy contributes to mitochondrial homeostasis, redox balance, and cellular stress adaptation. This review summarizes recent progress in understanding the molecular mechanisms and physiological significance of BNIP3/NIX-dependent mitophagy.

DOI: https://doi.org/10.1093/jb/mvag048

Nat Commun. 2026 Jun 30. pii: 5552. [Epub ahead of print]17(1):

Gravitational and mechanical forces shape mitochondrial translation.

Taisei Wakigawa, Yusuke Kimura, Mari Mito, Toshiya Tsubaki, Muhoon Lee, Koki Nakamura, Abdul Haseeb Khan, Hironori Saito, Tohru Yamamori, Tomokazu Yamazaki, Akira Higashibata, Tatsuhisa Tsuboi, Yusuke Hirabayashi, Nono Takeuchi-Tomita, Taku Saito, Atsushi Higashitani, Yuichi Shichino, Shintaro Iwasaki.

Life on Earth has evolved in a form suitable for the gravitational force. Although the pivotal role of gravity in gene expression has been suggested, the molecular details remain unclear. Here, we show that mitochondria utilize gravity to activate protein synthesis within the organelle. Genome-wide ribosome profiling reveals reduced mitochondrial translation in mammalian cells and Caenorhabditis elegans under microgravity. We found that attenuation of cell adhesion through laminin-integrin interactions caused the phenotype. Mitochondrial translation is activated by a signal relayed by FAK, RAC1, PAK1, BAD, and Bcl-2 family proteins in the cytosol, and the mitochondrial fatty acid synthesis (mtFAS) pathway in the matrix. Consumption of mitochondrial malonyl-CoA by mtFAS reduces the malonylation of the translational machinery and accelerates the rates of translational initiation and elongation. Physiologically, this system operates in mechano-response of skeletal muscles. Our work provides mechanistic insights into how cells convert gravitational and mechanical forces into translation in mitochondria.

DOI: https://doi.org/10.1038/s41467-026-74493-z