What are stress fibers? Stress fibers are higher order cytoskeletal structures composed of cross-linked actin filament bundles, and in many cases, myosin motor proteins, that span a length of 1-2 micrometers [1]. At least 4 types of stress fibers have been identified in mammalian [...]
What is the function of stress fibers? Stress fibers are contractile in nature. By exerting and maintaining tension on the underlying substratum, they form a key element of the mechanotransduction apparatus that links the cell interior and exterior. The organization of stress fibers resembles [...]
What mechanisms drive invadopodia extension? Following initiation by an appropriate signal, the actin cytoskeleton is reorganized to facilitate invadopodia formation. Although several kinases and GTPases are known to influence the transduction of extracellular signaling events leading to F-actin nucleation, there is currently no clear [...]
How do invadopodia degrade the extracellular matrix? The main function attributed to invadopodia is that of extracellular matrix (ECM) degradation, facilitated by the secretion of proteases. Maintenance of this process requires the delivery of new proteases from the Golgi, which is conveniently positioned in [...]
What is the first step in invadopodia assembly? Initiation of invadopdia formation is highly complex, being influenced by various signalling cascades and phosphorylation events that occur following detection of a stimulant. For example, activation of the epidermal growth factor (EGF) receptor by EGF has [...]
What are podosomes? Podosomes are actin-rich, adhesive structures that are present at the ventral surface of cells of the monocytic myeloid lineage, stimulated endothelial cells [1] and cultured Src-transformed cancer cells. These structures are not limited to the cell periphery, but do exhibit a [...]
What are the functions of podosomes? Both focal adhesions and podosomes are intimately involved in cell motility, with podosomes specifically implicated in cell invasion. Invasiveness is achieved through the secretion of matrix metalloproteinases (MMPs) from the core of podosomes, which degrade the extracellular matrix [...]
How do motor proteins transport cargo along the cytoskeleton? Along with providing structural support to the cell, and transmitting force signals, cytoskeletal filaments also provide cells with a network of ‘tracks’ that can be followed by specific proteins for the directed delivery of vesicles [...]
What is Myosin? An Introduction to the Myosin Superfamily of Proteins Myosin I has unique tail domain(s) relative to other myosin members which allows myosin I to bind to membrane lipids or to more than one actin filament at a time (see panel ‘A’ [...]
What are the steps in dorsal stress fiber formation? Dorsal stress fibers in motile cells are formed from actin filament bundles that are initiated and extended from cell-substrate adhesions at the leading edge (aka focal complexes [FXs]) (reviewed in [1]). Similar to graded polarity [...]
What are the steps in the formation of transverse arcs? In general, initiation of stress fiber formation is modulated by signaling cascades involving RhoA small GTPase [1] (reviewed in [2]). Most G-actin polymerization is driven by the actin polymerizing machinery at the barbed end [...]
What are the steps in ventral stress fiber formation? Recent data suggests that ventral stress fibers are created by reorganizing pre-existing dorsal stress fibers and transverse arcs [1].Other contrasting models for the formation of ventral stress fibers not covered in this resource include annealing [...]
A leading global university centred in Asia, NUS is Singapore's flagship university, offering a global approach to education and research with a focus on Asian perspectives and expertise.
One of four Research Centres of Excellence at NUS, MBI is working to identify, measure and describe how the forces for motility and morphogenesis are expressed at the molecular, cellular and tissue level.