Feng-Ching Tsai

Institut Curie · Département de Physicochimie du vivant

Filopodia are actin-rich membrane protrusions essential for cell morphogenesis, motility, and cancer invasion. How cells control filopodium initiation on the plasma membrane remains elusive. We performed experiments in cellulo, in vitro, and in silico to unravel the mechanism of filopodium initiation driven by the membrane curvature sensor IRSp53 (...

Intracellular trafficking is mediated by transport carriers that originate by membrane remodeling from donor organelles. Tubular carriers contribute to the flux of membrane lipids and proteins to acceptor organelles, but how lipids and proteins impose a tubular geometry on the carriers is incompletely understood. Using imaging approaches on cells a...

The spontaneous opening of large transendothelial cell macroaperture (TEM) tunnels can accompany leukocyte diapedesis and is triggered by bacterial exoenzymes that inhibit RhoA-driven cytoskeleton contractility. Modelling the dynamics of TEM via a theoretical framework used for soft matter physics allowed us to depict the essential driving forces a...

The endosomal sorting complexes required for transport (ESCRT) system is an ancient and ubiquitous membrane scission machinery that catalyzes the budding and scission of membranes. ESCRT-mediated scission events, exemplified by those involved in the budding of HIV-1, are usually directed away from the cytosol (“reverse topology”), but they can also...

Amphiphysin 2 (BIN1) is a membrane and actin remodeling protein mutated both in congenital and adult centronuclear myopathies. The BIN1 muscle-specific isoform finely tunes muscle regeneration in adulthood and regulates myoblast fusion. However, the underlying molecular mechanisms are unknown. Here, we report that BIN1 is required for myoblast fusi...

Filopodia are actin-rich membrane protrusions essential for cell morphogenesis, motility, and cancer invasion. How cells control filopodia initiation on the plasma membrane remains elusive. We performed experiments in cellulo, in vitro and in silico to unravel the mechanism of filopodia initiation driven by the membrane curvature sensor IRSp53. We...

The endosomal sorting complexes required for transport (ESCRT) system is an ancient and ubiquitous membrane scission machinery that catalyzes the budding and scission of membranes. ESCRT-mediated scission events, exemplified by those involved in the budding of HIV-1, are usually directed away from the cytosol (‘reverse-topology’), but they can also...

Cell membranes are highly deformable and can be strongly curved. For instance, cells extend thin and dynamic tubular plasma membrane protrusions for sensing their surroundings and for their motion called “filopodia.” These finger-like protrusions are formed by actin parallel filaments pushing against the membrane while they polymerize. How actin is...

Many signal transductions resulting from ligand-receptor interactions occur at the cell surface. These signaling pathways play essential roles in cell polarization, membrane morphogenesis, and the modulation of membrane tension at the cell surface. However, due to the large number of membrane-binding proteins, including actin-membrane linkers, and...

Intracellular trafficking is mediated by transport carriers that originate by membrane remodeling from donor organelles. Tubular carriers play major roles in the flux of membrane lipids and proteins to acceptor organelles. However, how lipids and proteins impose a tubular geometry on the carriers is incompletely understood. By exploiting imaging ap...

Septin GTP-binding proteins contribute essential biological functions that range from the establishment of cell polarity to animal tissue morphogenesis. Human septins in cells form hetero-octameric septin complexes containing the ubiquitously expressed SEPT9. Despite the established role of SEPT9 in mammalian development and human pathophysiology,...

During HIV-1 particle formation, the requisite plasma membrane curvature is thought to be solely driven by the retroviral Gag protein. Here, we reveal that the cellular I-BAR protein IRSp53 is required for the progression of HIV-1 membrane curvature to complete particle assembly. SiRNA-mediated knockdown of IRSp53 gene expression induces a decrease...

Protein enrichment at specific membrane locations in cells is crucial for many cellular functions. It is well-recognized that the ability of some proteins to sense membrane curvature contributes partly to their enrichment in highly curved cellular membranes. In the past, different theoretical models have been developed to reveal the physical mechan...

During HIV-1 particle formation, the requisite plasma membrane curvature is thought to be solely driven by the retroviral Gag protein. Here, we reveal that the cellular I-BAR protein IRSp53 is required for the progression of HIV-1 membrane curvature to complete particle assembly. Partial gene editing of IRSp53 induces a decrease in viral particle p...

Septin GTP-binding proteins contribute essential biological functions that range from the establishment of cell polarity to animal tissue morphogenesis. Human septins in cells form hetero-octameric septin complexes containing the ubiquitously expressed SEPT9. Despite the established role of SEPT9 in mammalian development and human pathophysiology,...

Protein-mediated membrane remodeling is a ubiquitous and critical process for proper cellular function. Inverse Bin/Amphiphysin/Rvs (I-BAR) domains drive local membrane deformation as a precursor to large-scale membrane remodeling. We employ a multiscale approach to provide the molecular mechanism of unusual I-BAR domain-driven membrane remodeling...

Cardiolipin is a cone-shaped lipid predominantly localized in curved membrane sites of bacteria and in the mitochondrial cristae. This specific localization has been argued to be geometry-driven, since the CL's conical shape relaxes curvature frustration. Although previous evidence suggests a coupling between CL concentration and membrane shape in...

Biosensors based on plasmonic nanostructures are widely used in various applications and benefit from numerous operational advantages. One type of application where nanostructured sensors provide unique value in comparison with, for instance, conventional surface plasmon resonance, is investigations of the influence of nanoscale geometry on biomole...

Septins are cytoskeletal filaments that assemble at the inner face of the plasma membrane. They are localized at constriction sites and impact membrane remodeling. We report in vitro tools to examine how yeast septins behave on curved and deformable membranes. Septins reshape the membranes of Giant Unilamellar Vesicles with the formation of periodi...

The shape of cellular membranes is highly regulated by a set of conserved mechanisms that can be manipulated by bacterial pathogens to infect cells. Remodeling of the plasma membrane of endothelial cells by the bacterium Neisseria meningitidis is thought to be essential during the blood phase of meningococcal infection, but the underlying mechanism...

One challenge in cell biology is to decipher the biophysical mechanisms governing protein enrichment on curved membranes and the resulting membrane deformation. The ERM protein ezrin is abundant and associated with cellular membranes that are flat, positively or negatively curved. Using in vitro and cell biology approaches, we assess mechanisms of...

Source data of Figure 1—figure supplement 1C and D.

Source data of Figure 4—figure supplement 1A and B.

Source data of Figure 1—figure supplement 1G.

The shape of cellular membranes is highly regulated by a set of conserved mechanisms. These mechanisms can be manipulated by bacterial pathogens to infect cells. Human endothelial cell plasma membrane remodeling by the bacterium Neisseria meningitidis is thought to be essential during the blood phase of meningococcal infection, but the underlying m...

One challenge in current cell biology is to decipher the biophysical mechanisms governing protein enrichment on curved membranes and the resulting membrane deformation. The ERM protein ezrin is abundant and associated with cellular membranes that are flat or with positive or negative curvatures. Using in vitro and cell biology approaches, we assess...

The reshaping of the cell membrane is an integral part of many cellular phenomena, such as endocytosis, trafficking, the formation of filopodia, etc. Many different proteins associate with curved membranes because of their ability to sense or induce membrane curvature. Typically, these processes involve a multitude of proteins making them too compl...

Septins are guanine nucleotide–binding proteins that are conserved from fungi to humans. Septins assemble into heterooligomeric complexes and higher-order structures with key roles in various cellular functions including cell migration and division. The mechanisms by which septins assemble and interact with other cytoskeletal elements like actin re...

In living cells, lipid membranes and biopolymers determine each other's conformation in a delicate force balance. Cellular polymers such as actin filaments are strongly confined by the plasma membrane in cell protrusions such as lamellipodia and filopodia. Conversely, protrusion formation is facilitated by actin-driven membrane deformation and thes...

Filamentous biopolymer networks in cells and tissues are routinely imaged by confocal microscopy. Image analysis methods enable quantitative study of the properties of these curvilinear networks. However, software tools to quantify the geometry and topology of these often dense 3D networks and to localize network junctions are scarce. To fill this...

Shape changes of animal cells during cell division, migration, and tissue morphogenesis depend on an interplay between the plasma membrane and the cytoskeleton. The actin and microtubule cytoskeleton provide mechanical support to the plasma membrane but also exert active forces to deform the membrane. The molecular complexity of cells makes it diff...

Animal cell cytokinesis requires a contractile ring of crosslinked actin filaments and myosin motors. How contractile rings form and are stabilized in dividing cells remains unclear. We address this problem by focusing on septins, highly conserved proteins in eukaryotes whose precise contribution to cytokinesis remains elusive. We use the cleavage...

Significance Animal cells continuously move, divide, and transmit forces by actively reorganizing their internal scaffold or cytoskeleton. Molecular motors pull actin filaments together and generate contraction of the cytoskeleton underneath the cell membrane. We address the detailed mechanism of contraction by using a minimal in vitro assay: a lip...

Giant unilamellar vesicles or GUVs are systems of choice as biomimetic models of cellular membranes. Although a variety of procedures exist for making single walled vesicles of tens of microns in size, the range of lipid compositions that can be used to grow GUVs by the conventional methods is quite limited, and many of the available methods involv...

We demonstrate that cytoskeletal actin-myosin networks can be encapsulated with high efficiency in giant liposomes by hydration of lipids in an agarose hydrogel. The liposomes have cell-sized diameters of 10-20 μm and a uniform actin content. We show by measurements of membrane fluorescence intensity and bending rigidity that the majority of liposo...

Gold nanoparticles (AuNPs) confined in liposomes of diameters around 200 nm produce strong scattering signal owing to surface plasmon resonance, and therefore bright-field optical tracking of the AuNP-encapsulating liposomes can be conducted in living cells. Using an optical profiling technique called noninterferometric wide-field optical profilome...

We measure the temporal evolution of three-dimensional membrane topography on living fibroblasts and characterize the propagation of membrane waves using a wide-field optical profiling technique. The measured membrane profiles are compared with the numerical results calculated by the active membrane model recently proposed by Shlomovitz and Gov. Af...

A theoretical model for vesicle fission induced by particle adsorption and aggregation on a membrane surface is presented. The bulk fluid contains particles that are adsorbed reversibly to the membrane. Adsorbed particles aggregate on the membrane, forming particle-rich domains. Domains at a critical size which contains nv particles become vesicles...