Mitochondrial Cell‐Type‐Specific Profiling: Differential Function of Mesophyll and Guard Cells is Reflected by Their Mitochondrial Proteome

作者：Friederike Hater, Jürgen Eirich, Paulina Heinkow, Saurabh Joshi, Yara Ehlert, Joakim Palovaara, Isil Erbasol Serbes, Amina Brahmia, Marco Diederichs, Sadaf Jalili, Nayanika Mukherjee, Paul Ssemanda, Annette Peter, Ole Schweser, Martin Kubitschke, Murali Krishna Madduri, Janine Kirstein, Kathrin Maedler, Olivia Andrea Masseck, Iris Finkemeier, Rita Groß‐Hardt · 发表于：Physiologia Plantarum · 年份：2025 · DOI：10.1111/ppl.70579 · 被引用次数：3 · 研究领域：Photosynthetic Processes and Mechanisms、Mitochondrial Function and Pathology、ATP Synthase and ATPases Research

Cell specification and ensuing division of labor enable the accomplishment of complex tasks in multicellular organisms. In plants, mesophyll and guard cells exhibit striking functional, metabolic, and mechanophysical differences: mesophyll cells are highly specialized for efficient light-energy conversion, whereas guard cells regulate gas exchange. Here, we address whether the cellular specialization is sustained by mitochondrial diversity between cells. We developed mRACE (RApid CEll-type-specific isolation of mitochondria), an innovative method for rapid cell-type-specific mitochondrial isolation. mRACE involves biotin labeling of mitochondria in target cells, followed by affinity-based organelle enrichment with streptavidin-coated microbeads or immobilization on functionalized glass slides. Using mitochondrial activity modulators, we confirmed that mRACE-isolated mitochondria remain physiologically active, validating their suitability for downstream analyses. Applying mRACE, we isolated mitochondria from mesophyll and guard cells and performed a comprehensive proteome analysis. Notably, guard cells are enriched in active branched-chain amino acid (BCAA) catabolism components, suggesting they exploit this unconventional carbon source for energy. Additionally, the two cell types differ in ribosomal protein composition and RNA-editing proteins, highlighting mitochondrial specialization at multiple regulatory levels. We investigated gene activity for seven proteins differentia...