Septins as membrane influencers: direct play or in association with other cytoskeleton partners

Benoit, Béatrice; Poüs, Christian; Baillet, Anita

doi:10.3389/fcell.2023.1112319

Cited by 17 publications

(19 citation statements)

References 155 publications

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“…During plasma membrane repair, the remodeled septins closely associate with F-actin, myosin IIA, and ANXA2 throughout the cell surface and within the septin knobs and loops (Figures 2 to 5 and SF 4 to 6). Super-resolution microscopy allowed for visualization of intertwined F-actin and septin filaments in the septin loops (Figure 5), in accordance with the role of septins in bending actin filaments [25]. The septins mostly run parallel to the F-actin and, at times, appear perpendicular as if interconnecting actin fibers (Figure 5).…”

Section: Discussionmentioning

confidence: 67%

“…We found that SEPT2, SEPT7, and SEPT9 display similar labeling patterns in all experimental conditions. This was expected since septins of different groups co-assemble to form hexamers (SEPT-2,-6,-7,-7,-6,-2) and octamers (SEPT- 2,-6,-7,-9,-9,-7,-6,-2) [25]. We observed that septin filaments predominantly colocalized with actin stress fibers in control untreated cells (Figure 2Aa, SF 4Aa, Ba).…”

Section: Resultsmentioning

confidence: 99%

“…As shown in Figure 3A, the knob- and loop-like septin/F-actin structures also strongly colocalized with myosin-IIA indicating that the newly formed structures are contractile. As the septins have been proposed to regulate plasma membrane properties [25], we thought that the septins may control the organization of plasma membrane repair domains. To test this hypothesis, we investigated if the remodeled septins co-distribute with known plasma membrane repair machineries.…”

Section: Resultsmentioning

confidence: 99%

“…Of those, we focused on septin 7 (SEPT7) because the septins are an important family of highly conserved eukaryotic GTP-binding proteins described as the fourth component of the cytoskeleton after F-actin, microtubules, and intermediate filaments [24]. Human septins include 13 members which assemble into hetero-hexamers (SEPT-2,-6,-7,-7,-6,-2) and hetero-octamers (SEPT-2,-6,-7,-9,- 9,-7,-6,-2) that further organize into filaments or rings in association with F-actin, microtubules or the plasma membrane [25, 26]. They form filaments and rings that determine the shape, curvature, and properties of the plasma membrane [25, 27].…”

Section: Introductionmentioning

confidence: 99%

“…Human septins include 13 members which assemble into hetero-hexamers (SEPT-2,-6,-7,-7,-6,-2) and hetero-octamers (SEPT-2,-6,-7,-9,- 9,-7,-6,-2) that further organize into filaments or rings in association with F-actin, microtubules or the plasma membrane [25, 26]. They form filaments and rings that determine the shape, curvature, and properties of the plasma membrane [25, 27]. The septins control major cellular functions including cytokinesis, cell motility, tissue morphogenesis, and host-pathogen interactions [28, 29].…”

Section: Introductionmentioning

confidence: 99%

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The Septin Cytoskeleton is Required for Plasma Membrane Repair

Prislusky,

Lam,

Contreras

et al. 2023

Preprint

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Mammalian cells are frequently exposed to mechanical and biochemical stresses resulting in plasma membrane injuries. Repair mechanisms rapidly reseal the plasma membrane to restore homeostasis and prevent cell death. In the present work, a silencing RNA (siRNA) screen was performed to uncover the plasma membrane repair mechanisms of cells injured by the bacterial pore-forming toxin listeriolysin O (LLO). The screen identified a novel role for the septin cytoskeleton in mediating plasma membrane repair. Upon cell injury, the septin cytoskeleton partially dissociates from actin stress fibers and remodels with cortical F-actin and myosin-II to form loop (and ring)-like domains that protrude from the cell surface. These domains strictly colocalize with the calcium-dependent phospholipid-binding protein, annexin A2 (ANXA2). Importantly, formation of the SEPT/F-actin/ANXA2 domains are dependent on SEPT7 expression and is functionally correlated with the plasma membrane repair efficiency. Our studies open new research avenues by identifying a novel role for the septin cytoskeleton in remodeling the plasma membrane for its repair.

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Section: Discussionmentioning

confidence: 67%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The Septin Cytoskeleton is Required for Plasma Membrane Repair

Prislusky,

Lam,

Contreras

et al. 2023

Preprint

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Septin complexes: Ahead of the curve

Nakamura,

Parkhurst

2024

Cytoskeleton

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Individual cells have robust repair systems to survive cell cortex damage caused by mechanical and chemical stresses, allowing them to maintain the integrity of tissues and organs. The contraction of an actomyosin ring at the wound edge is a major mechanism for physically closing the cell wound. In contrast to polymerization and bundling of actin filaments, little is known about how linear actin filaments are bent to be integrated into the actin ring structure encircling the wound edge. We recently found that the five Drosophila Septins function simultaneously in the regulation of actomyosin ring assembly, contraction, and disassembly during cell wound repair. These Septins form two distinct complexes—Sep1‐Sep2‐Pnut and Sep4‐Sep5‐Pnut—composed of different subunits from the same groups. Strikingly, these two distinct Septin complexes have different degrees of F‐actin bending activities that are consistent with their spatial recruitment: different degrees of curved actin filaments are required for the robust formation of different regions of the actomyosin ring. In addition, we found that the two Septin complexes are regulated by different molecular pathways as a loss of Anillin only affects Sep1‐Sep2‐Pnut complex recruitment. These findings open new directions for how individual Septin subunits form complexes and function differentially in cellular and developmental processes.

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Septins: Structural Insights, Functional Dynamics, and Implications in Health and Disease

Das,

Kunwar

2024

J of Cellular Biochemistry

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Septins are a class of proteins with diverse and vital roles in cell biology. Structurally, they form hetero‐oligomeric complexes and assemble into filaments, contributing to the organization of cells. These filaments act as scaffolds, aiding in processes like membrane remodeling, cytokinesis, and cell motility. Functionally, septins are essential to cell division, playing essential roles in cytokinetic furrow formation and maintaining the structural integrity of the contractile ring. They also regulate membrane trafficking and help organize intracellular organelles. In terms of physiology, septins facilitate cell migration, phagocytosis, and immune responses by maintaining membrane integrity and influencing cytoskeletal dynamics. Septin dysfunction is associated with pathophysiological conditions. Mutations in septin genes have been linked to neurodegenerative diseases, such as hereditary spastic paraplegias, underscoring their significance in neuronal function. Septins also play a role in cancer and infectious diseases, making them potential targets for therapeutic interventions. Septins serve as pivotal components of intracellular signaling networks, engaging with diverse proteins like kinases and phosphatases. By modulating the activity of these molecules, septins regulate vital cellular pathways. This integral role in signaling makes septins central to orchestrating cellular responses to environmental stimuli. This review mainly focuses on the human septins, their structural composition, regulatory functions, and implication in pathophysiological conditions underscores their importance in fundamental cellular biology. Moreover, their potential as therapeutic targets across various diseases further emphasizes their significance.

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Septins as membrane influencers: direct play or in association with other cytoskeleton partners

Cited by 17 publications

References 155 publications

The Septin Cytoskeleton is Required for Plasma Membrane Repair

The Septin Cytoskeleton is Required for Plasma Membrane Repair

Septin complexes: Ahead of the curve

Septins: Structural Insights, Functional Dynamics, and Implications in Health and Disease

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