Intercellular junction assembly, dynamics, and homeostasis.
http://www.ncbi.nlm.nih.gov –
Intercellular anchoring junctions are highly specialized regions of the plasma membrane where members of the cadherin family of transmembrane adhesion molecules on opposing cells interact through their extracellular domains, and through their cytoplasmic domains serve as a platform for organizing cytoskeletal anchors and remodelers. Here we focus on assembly of so-called "anchoring" or "adhering" junctions-adherens junctions (AJs) and desmosomes (DSMs), which associate with actin and intermediate filaments, respectively. Read more »

Category: Focal Adhesions Tags:
Stretchy Proteins on Stretchy Substrates: The Important Elements of Integrin-Mediated Rigidity Sensing
http://www.sciencedirect.com –
Matrix and tissue rigidity guides many cellular processes, including the differentiation of stem cells and the migration of cells in health and disease. Cells actively and transiently test rigidity using mechanisms limited by inherent physical parameters that include the strength of extracellular attachments, the pulling capacity on these attachments, and the sensitivity of the mechanotransduction system. Read more »

Category: Focal Adhesions Tags:
TRP channels as cellular sensors
https://medschool.mc.vanderbilt.edu –
The human genome encodes hundreds of channels that broker the passage of charged ions across impermeable lipid bilayers1. While energy-requiring pumps labour to build charge and concentration gradients across the membrane, ion channels spend this stored energy, much as a switch releases the electrical energy of a battery. Small conformational changes cause channels to open, allowing over ten million ions to flow per second through each channel. Read more »

Category: Mechanosensors in Sensory Cells Tags:
Filamins in Mechanosensing and Signaling
http://www.annualreviews.org –
Filamins are essential, evolutionarily conserved, modular, multidomain, actin-binding proteins that organize the actin cytoskeleton and maintain extracellular matrix connections by anchoring actin filaments to transmem- brane receptors. By cross-linking and anchoring actin filaments, filamins sta- bilize the plasma membrane, provide cellular cortical rigidity, and contribute to the mechanical stability of the plasma membrane and the cell cortex. Read more »

Category: Mechanosensors in Sensory Cells Tags:
Mechanotransduction from the ECM to the genome: are the pieces now in place?
http://www.ncbi.nlm.nih.gov –
A multitude of biochemical signaling processes have been characterized that affect gene expression and cellular activity. However, living cells often need to integrate biochemical signals with mechanical information from their microenvironment as they respond. In fact, the signals received by shape alone can dictate cell fate. This mechanotrasduction of information is powerful, eliciting proliferation, differentiation, or apoptosis in a manner dependent upon the extent of physical deformation. Read more »

Category: Molecular Mechanotransduction Tags:
Bridging membrane and cytoskeleton dynamics in the secretory and endocytic pathways.
http://www.ncbi.nlm.nih.gov –
Transport carriers regulate membrane flow between compartments of the secretory and endocytic pathways in eukaryotic cells. Carrier biogenesis is assisted by microtubules, actin filaments and their associated motors that link to membrane-associated coats, adaptors and accessory proteins. We summarize here how the biochemical properties of membranes inform their interactions with cytoskeletal regulators. We also discuss how the forces generated by the cytoskeleton and motor proteins alter the biophysical properties and the shape of membranes. Read more »

Category: Cytoskeletal Dynamics Tags:
Regulation of the actin cytoskeleton in dendritic spines.
http://www.ncbi.nlm.nih.gov –
Spine morphogenesis is largely dependent on the remodeling of the actin cytoskeleton. Actin dynamics within spines is regulated by a complex network of signaling molecules, which relay signals from synaptic receptors, through small GTPases and their regulators, to actin-binding proteins. In this chapter, we will discuss molecules involved in dendritic spine plasticity beginning with actin and moving upstream toward neuromodulators and trophic factors that initiate signaling involved in these plasticity events. Read more »

Category: Cytoskeletal Dynamics Tags:
Rho Kinase Proteins—Pleiotropic Modulators of Cell Survival and Apoptosis
http://www.ncbi.nlm.nih.gov –
Rho kinase (ROCK) proteins are Rho-GTPase activated serine/threonine kinases that function as modulators of actin-myosin cytoskeletal dynamics via regulation of Lin11, Isl-1 & Mec-3 domain (LIM) kinase, myosin light chain (MLC), and MLC phosphatase. A strong correlation between cytoskeletal rearrangements and tumor cell invasion, metastasis, and deregulated microenvironment interaction has been reported in the literature, and the utilization of pharmacological inhibitors of ROCK signaling for the treatment of cancer is actively being pursued by a number of pharmaceutical companies. Read more »

Category: Cytoskeletal Dynamics Tags:
Regulation of small GTPases at epithelial cell-cell junctions.
http://www.molbio.unige.ch –
Small GTPases of the Rho family (RhoA, Rac1, and Cdc42) and the Ras family GTPase Rap1 are essential for the assembly and function of epithelial cell-cell junctions. Through their downstream effectors, small GTPases modulate junction formation and stability, primarily by orchestrating the polymerization and contractility of the actomyosin cytoskeleton. The major upstream regulators of small GTPases are guanine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs). Read more »

Category: Adherens Junctions Tags:
The nucleoskeleton as a genome-associated dynamic 'network of networks'.
http://www.ncbi.nlm.nih.gov –
In the cytosol, actin polymers, intermediate filaments and microtubules can anchor to cell surface adhesions and interlink to form intricate networks. This cytoskeleton is anchored to the nucleus through LINC (links the nucleoskeleton and cytoskeleton) complexes that span the nuclear envelope and in turn anchor to networks of filaments in the nucleus. Read more »
Year of publication:
2011
Journal name:
Nature Reviews Molecular Cell Biology

Category: Molecular Mechanotransduction Tags:
Cytoskeleton dynamics: fluctuations within the network.
http://www.ncbi.nlm.nih.gov –
Out-of-equilibrium systems, such as the dynamics of a living cytoskeleton (CSK), are inherently noisy with fluctuations arising from the stochastic nature of the underlying biochemical and molecular events. Recently, such fluctuations within the cell were characterized by observing spontaneous nano-scale motions of an RGD-coated microbead bound to the cell surface [Bursac et al., Nat. Mater. 4 (2005) 557-561]. Read more »

Category: Cytoskeletal Dynamics Tags:
Unleashing formins to remodel the actin and microtubule cytoskeletons.
http://www.ncbi.nlm.nih.gov –
Formins are highly conserved proteins that have essential roles in remodelling the actin and microtubule cytoskeletons to influence eukaryotic cell shape and behaviour. Recent work has identified numerous cellular factors that locally recruit, activate or inactivate formins to bridle and unleash their potent effects on actin nucleation and elongation. The effects of formins on microtubules have also begun to be described, which places formins in a prime position to coordinate actin and microtubule dynamics. Read more »

Category: Cytoskeletal Dynamics Tags:
A nucleator arms race: cellular control of actin assembly.
http://www.ncbi.nlm.nih.gov –
For over a decade, the actin-related protein 2/3 (ARP2/3) complex, a handful of nucleation-promoting factors and formins were the only molecules known to directly nucleate actin filament formation de novo. However, the past several years have seen a surge in the discovery of mammalian proteins with roles in actin nucleation and dynamics. Read more »

Category: Cytoskeletal Dynamics Tags:
Control of polarized cell morphology and motility by adherens junctions.
http://www.ncbi.nlm.nih.gov –
Cell-cell interactions play a key role in tissue homeostasis. Intercellular adhesions share the complex task of establishing and maintaining tissue architecture while allowing tissue growth, renewal and repair. In particular, adherens junctions (AJs) have been implicated in the formation of diverse tissues and organs like epitheliums, blood vessels or the central nervous system. At the cellular level, AJs are well known for their essential role in epithelial cell differentiation and baso-apical polarity. Read more »

Category: Adherens Junctions Tags:
Spectraplakins: Master orchestrators of cytoskeletal dynamics.
http://www.ncbi.nlm.nih.gov –
The dynamics of different cytoskeletal networks are coordinated to bring about many fundamental cellular processes, from neuronal pathfinding to cell division. Increasing evidence points to the importance of spectraplakins in integrating cytoskeletal networks. Spectraplakins are evolutionarily conserved giant cytoskeletal cross-linkers, which belong to the spectrin superfamily. Their genes consist of multiple promoters and many exons, yielding a vast array of differential splice forms with distinct functions. Read more »

Category: Cytoskeletal Dynamics Tags:
Cell-cell connectivity: desmosomes and disease.
http://www.ncbi.nlm.nih.gov –
Cell-cell connectivity is an absolute requirement for the correct functioning of cells, tissues and entire organisms. At the level of the individual cell, direct cell-cell adherence and communication is mediated by the intercellular junction complexes: desmosomes, adherens, tight and gap junctions. A broad spectrum of inherited, infectious and auto-immune diseases can affect the proper function of intercellular junctions and result in either diseases affecting specific individual tissues or widespread syndromic conditions. Read more »

Category: Adherens Junctions Tags:
Focal adhesion kinase and tumour angiogenesis.
http://www.ncbi.nlm.nih.gov –
Angiogenesis, the formation of new blood vessels from pre-existing ones, is essential for tumour development. It is initiated and regulated by growth factors via their surface receptors, which activate several intracellular signalling pathways in endothelial cells. Cell adhesion molecules, such as integrins, also regulate angiogenesis. Despite these facts, inhibitors of endothelial cell growth factor receptors or integrins have not been as effective as initially hoped in the long-term inhibition of angiogenesis in cancer patients. Read more »

Category: Focal Adhesions Tags:
The molecular basis of mechanosensory transduction.
http://www.ncbi.nlm.nih.gov –
Multiple senses, including hearing, touch and osmotic regulation, require the ability to convert force into an electrical signal: A process called mechanotransduction. Mechanotransduction occurs through specialized proteins that open an ion channel pore in response to a mechanical stimulus. Many of these proteins remain unidentified in vertebrates, but known mechanotransduction channels in lower organisms provide clues into their identity and mechanism. Bacteria, fruit flies and nematodes have all been used to elucidate the molecules necessary for force transduction. Read more »

Category: Mechanosensors in Sensory Cells Tags:
