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Read TA, Cisterna BA, Skruber K, Ahmadieh S, Liu TM, Vitriol JA, Shi Y, Black JB, Butler MT, Lindamood HL, Lefebvre AE, Cherezova A, Ilatovskaya DV, Bear JE, Weintraub NL, Vitriol EA. The actin binding protein profilin 1 localizes inside mitochondria and is critical for their function. EMBO Rep 2024; 25:3240-3262. [PMID: 39026010 PMCID: PMC11316047 DOI: 10.1038/s44319-024-00209-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 06/16/2024] [Accepted: 06/28/2024] [Indexed: 07/20/2024] Open
Abstract
The monomer-binding protein profilin 1 (PFN1) plays a crucial role in actin polymerization. However, mutations in PFN1 are also linked to hereditary amyotrophic lateral sclerosis, resulting in a broad range of cellular pathologies which cannot be explained by its primary function as a cytosolic actin assembly factor. This implies that there are important, undiscovered roles for PFN1 in cellular physiology. Here we screened knockout cells for novel phenotypes associated with PFN1 loss of function and discovered that mitophagy was significantly upregulated. Indeed, despite successful autophagosome formation, fusion with the lysosome, and activation of additional mitochondrial quality control pathways, PFN1 knockout cells accumulate depolarized, dysmorphic mitochondria with altered metabolic properties. Surprisingly, we also discovered that PFN1 is present inside mitochondria and provide evidence that mitochondrial defects associated with PFN1 loss are not caused by reduced actin polymerization in the cytosol. These findings suggest a previously unrecognized role for PFN1 in maintaining mitochondrial integrity and highlight new pathogenic mechanisms that can result from PFN1 dysregulation.
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Affiliation(s)
- Tracy-Ann Read
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA.
| | - Bruno A Cisterna
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Kristen Skruber
- Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA, USA
| | - Samah Ahmadieh
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA, USA
- Department of Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Tatiana M Liu
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Josefine A Vitriol
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Yang Shi
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
- Department of Population Health Sciences, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Joseph B Black
- Division of Urologic Surgery, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Mitchell T Butler
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA
| | - Halli L Lindamood
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | | | - Alena Cherezova
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Daria V Ilatovskaya
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - James E Bear
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA
| | - Neal L Weintraub
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA, USA
- Department of Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Eric A Vitriol
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA.
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Cvrčková F, Ghosh R, Kočová H. Transmembrane formins as active cargoes of membrane trafficking. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:3668-3684. [PMID: 38401146 PMCID: PMC11194305 DOI: 10.1093/jxb/erae078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 02/23/2024] [Indexed: 02/26/2024]
Abstract
Formins are a large, evolutionarily old family of cytoskeletal regulators whose roles include actin capping and nucleation, as well as modulation of microtubule dynamics. The plant class I formin clade is characterized by a unique domain organization, as most of its members are transmembrane proteins with possible cell wall-binding motifs exposed to the extracytoplasmic space-a structure that appears to be a synapomorphy of the plant kingdom. While such transmembrane formins are traditionally considered mainly as plasmalemma-localized proteins contributing to the organization of the cell cortex, we review, from a cell biology perspective, the growing evidence that they can also, at least temporarily, reside (and in some cases also function) in endomembranes including secretory and endocytotic pathway compartments, the endoplasmic reticulum, the nuclear envelope, and the tonoplast. Based on this evidence, we propose that class I formins may thus serve as 'active cargoes' of membrane trafficking-membrane-embedded proteins that modulate the fate of endo- or exocytotic compartments while being transported by them.
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Affiliation(s)
- Fatima Cvrčková
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, CZ 128 43 Praha 2, Czechia
| | - Rajdeep Ghosh
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, CZ 128 43 Praha 2, Czechia
| | - Helena Kočová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, CZ 128 43 Praha 2, Czechia
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Wu Y, Ren X, Shi P, Wu C. Regulation of mitochondrial structure by the actin cytoskeleton. Cytoskeleton (Hoboken) 2024; 81:206-214. [PMID: 37929797 DOI: 10.1002/cm.21804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 10/16/2023] [Accepted: 10/22/2023] [Indexed: 11/07/2023]
Abstract
Mitochondria are the powerhouse of the cell and play important roles in multiple cellular processes including cell metabolism, proliferation, and programmed cell death. Mitochondria are double-membrane organelles with the inner membrane folding inward to form cristae. Mitochondria networks undergo dynamic fission and fusion. Deregulation of mitochondrial structure has been linked to perturbed mitochondrial membrane potential and disrupted metabolism, as evidenced in tumorigenesis, neurodegenerative diseases, etc. Actin and its motors-myosins have long been known to generate mechanical forces and participate in short-distance cargo transport. Accumulating knowledge from biochemistry and live cell/electron microscope imaging has demonstrated the role of actin filaments in pre-constricting the mitochondria during fission. Recent studies have suggested the involvement of myosins in cristae maintenance and mitochondria quality control. Here, we review current findings and discuss future directions in the emerging fields of cytoskeletal regulation in cristae formation, mitochondrial dynamics, intracellular transport, and mitocytosis, with focus on the actin cytoskeleton and its motor proteins.
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Affiliation(s)
- Yihe Wu
- Institute of Systems Biomedicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Xiaoyu Ren
- Institute of Systems Biomedicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Peng Shi
- Institute of Systems Biomedicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
- International Cancer Institute, Peking University, Beijing, China
| | - Congying Wu
- Institute of Systems Biomedicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
- International Cancer Institute, Peking University, Beijing, China
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Merta H, Isogai T, Paul B, Danuser G, Henne WM. Spatial proteomics of ER tubules reveals CLMN, an ER-actin tether at focal adhesions that promotes cell migration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.24.577043. [PMID: 38328045 PMCID: PMC10849733 DOI: 10.1101/2024.01.24.577043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
The endoplasmic reticulum (ER) is structurally and functionally diverse, yet how its functions are organized within morphological subdomains is incompletely understood. Utilizing TurboID-based proximity labeling and CRISPR knock-in technologies, here we map the proteomic landscape of the human ER and nuclear envelope. Spatial proteomics reveals enrichments of proteins into ER tubules, sheets, and nuclear envelope. We uncover an ER-enriched actin-binding protein, Calmin (CLMN), and define it as an ER-actin tether that localizes to focal adhesions adjacent to ER tubules. CLMN depletion perturbs focal adhesion disassembly, actin dynamics, and cell movement. Mechanistically, CLMN-depleted cells also exhibit defects in calcium signaling near ER-actin interfaces, suggesting CLMN promotes calcium signaling near adhesions to facilitate their disassembly. Collectively, we map the sub-organelle proteome landscape of the ER, identify CLMN as an ER-actin tether, and describe a non-canonical mechanism by which ER tubules engage actin to regulate cell migration.
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Affiliation(s)
- Holly Merta
- Department of Cell Biology, UT Southwestern Medical Center, Dallas TX 75390
| | - Tadamoto Isogai
- Lyda Hill Department of Bioinformatics and Cecil H. and Ida Green Center for Systems Biology, UT Southwestern Medical Center, Dallas TX 75390
| | - Blessy Paul
- Department of Cell Biology, UT Southwestern Medical Center, Dallas TX 75390
| | - Gaudenz Danuser
- Department of Cell Biology, UT Southwestern Medical Center, Dallas TX 75390
- Lyda Hill Department of Bioinformatics and Cecil H. and Ida Green Center for Systems Biology, UT Southwestern Medical Center, Dallas TX 75390
| | - W Mike Henne
- Department of Cell Biology, UT Southwestern Medical Center, Dallas TX 75390
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Read TA, Cisterna BA, Skruber K, Ahmadieh S, Lindamood HL, Vitriol JA, Shi Y, Lefebvre AE, Black JB, Butler MT, Bear JE, Cherezova A, Ilatovskaya DV, Weintraub NL, Vitriol EA. The actin binding protein profilin 1 is critical for mitochondria function. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.07.552354. [PMID: 37609280 PMCID: PMC10441311 DOI: 10.1101/2023.08.07.552354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Profilin 1 (PFN1) is an actin binding protein that is vital for the polymerization of monomeric actin into filaments. Here we screened knockout cells for novel functions of PFN1 and discovered that mitophagy, a type of selective autophagy that removes defective or damaged mitochondria from the cell, was significantly upregulated in the absence of PFN1. Despite successful autophagosome formation and fusion with the lysosome, and activation of additional mitochondrial quality control pathways, PFN1 knockout cells still accumulate damaged, dysfunctional mitochondria. Subsequent imaging and functional assays showed that loss of PFN1 significantly affects mitochondria morphology, dynamics, and respiration. Further experiments revealed that PFN1 is located to the mitochondria matrix and is likely regulating mitochondria function from within rather than through polymerizing actin at the mitochondria surface. Finally, PFN1 mutants associated with amyotrophic lateral sclerosis (ALS) fail to rescue PFN1 knockout mitochondrial phenotypes and form aggregates within mitochondria, further perturbing them. Together, these results suggest a novel function for PFN1 in regulating mitochondria and identify a potential pathogenic mechanism of ALS-linked PFN1 variants.
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Affiliation(s)
- Tracy-Ann Read
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Bruno A. Cisterna
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Kristen Skruber
- Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA, USA
| | - Samah Ahmadieh
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA, USA
- Department of Medicine, Medical College of Georgia at Augusta University, Augusta, Georgia, USA
| | - Halli L. Lindamood
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Josefine A. Vitriol
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Yang Shi
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
- Department of Population Health Sciences, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | | | - Joseph B. Black
- Division of Urologic Surgery, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Mitchell T. Butler
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA
| | - James E. Bear
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA
| | - Alena Cherezova
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Daria V. Ilatovskaya
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Neil L. Weintraub
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA, USA
- Department of Medicine, Medical College of Georgia at Augusta University, Augusta, Georgia, USA
| | - Eric A. Vitriol
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
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