bims-mitran 2025-05-11 papers

Issue of 2025–05–11
two papers selected by
Andreas Kohler, Umeå University

J Cell Sci. 2025 May 01. pii: jcs263753. [Epub ahead of print]138(9):

The role of mitochondrial mRNA translation in cellular communication.

Eleonora Zilio, Tim Schlegel, Marta Zaninello, Elena I Rugarli.

Mitochondria are dynamic and heterogeneous organelles that rewire their network and metabolic functions in response to changing cellular needs. To this end, mitochondria integrate a plethora of incoming signals to influence cell fate and survival. A crucial and highly regulated node of cell-mitochondria communication is the translation of nuclear-encoded mitochondrial mRNAs. By controlling and monitoring the spatio-temporal translation of these mRNAs, cells can rapidly adjust mitochondrial function to meet metabolic demands, optimise ATP production and regulate organelle biogenesis and turnover. In this Review, we focus on how RNA-binding proteins that recognise nuclear-encoded mitochondrial mRNAs acutely modulate the rate of translation in response to nutrient availability. We further discuss the relevance of localised translation of these mRNAs for subsets of mitochondria in polarised cells. Finally, we highlight quality control mechanisms that monitor the translation process at the mitochondrial surface and their connections to mitophagy and stress responses. We propose that these processes collectively contribute to mitochondrial specialisation and signalling function.

Keywords: Cell signalling; Mitochondria; RNA-binding proteins; Ribosome quality control; Translation; mRNA

DOI: https://doi.org/10.1242/jcs.263753

Mol Cell. 2025 May 02. pii: S1097-2765(25)00362-4. [Epub ahead of print]

Structural basis of human CHD1 nucleosome recruitment and pausing.

Allison M James, Lucas Farnung.

Chromatin remodelers regulate gene expression and genome maintenance by controlling nucleosome positioning, but the structural basis for their regulated and directional activity remains poorly understood. Here, we present three cryoelectron microscopy (cryo-EM) structures of human chromodomain helicase DNA-binding protein 1 (CHD1) bound to nucleosomes that reveal previously unobserved recruitment and regulatory states. We identify a structural element, termed the "anchor element," that connects the CHD1 ATPase motor to the nucleosome entry-side acidic patch. The anchor element coordinates with other regulatory modules, including the gating element, which undergoes a conformational switch critical for remodeling. Our structures demonstrate how the DNA-binding region of CHD1 binds entry- and exit-side DNA during remodeling to achieve directional sliding. The observed structural elements are conserved across chromatin remodelers, suggesting a unified mechanism for nucleosome recognition and remodeling. Our findings show how chromatin remodelers couple nucleosome recruitment to regulated DNA translocation, providing a framework for understanding chromatin remodeler mechanisms beyond DNA translocation.

Keywords: chromatin remodeling; cryo-EM; gene expression; genome organization; histone methylation; histone modification; nucleosome; nucleosome sliding; structural biology; transcription

DOI: https://doi.org/10.1016/j.molcel.2025.04.020