Wednesday, December 29, 2010

Hot off the presses! Jan 01 trends cell biol

The Jan 01 issue of the trends cell biol is now up on Pubget (About trends cell biol): if you're at a subscribing institution, just click the link in the latest link at the home page. (Note you'll only be able to get all the PDFs in the issue if your institution subscribes to Pubget.)

Latest Articles Include:

  • Contents page + Editorial Board
    - trends cell biol 21(1):i (2011)
  • Richard Pagano (1944–2010)
    - trends cell biol 21(1):1 (2011)
  • Dogma bites back – the evidence for branched actin
    - trends cell biol 21(1):2 (2011)
  • Discussing the morphology of actin filaments in lamellipodia
    - trends cell biol 21(1):2-4 (2011)
  • Actin networking in lamellipodia and beyond
    - trends cell biol 21(1):4-5 (2011)
  • The role of chromatin structure in cell migration
    - trends cell biol 21(1):6-11 (2011)
    Chromatin dynamics play a major role in regulating genetic processes. Now, accumulating data suggest that chromatin structure may also affect the mechanical properties of the nucleus and cell migration. Global chromatin organization appears to modulate the shape, the size and the stiffness of the nucleus. Directed-cell migration, which often requires nuclear reshaping to allow passage of cells through narrow openings, is dependent not only on changes in cytoskeletal elements but also on global chromatin condensation. Conceivably, during cell migration a physical link between the chromatin and the cytoskeleton facilitates coordinated structural changes in these two components. Thus, in addition to regulating genetic processes, we suggest that alterations in chromatin structure could facilitate cellular reorganizations necessary for efficient migration.
  • Fungal evo–devo: organelles and multicellular complexity
    - trends cell biol 21(1):12-19 (2011)
    Peroxisome-derived Woronin bodies of the Ascomycota phyla, and the endoplasmic reticulum (ER)-derived septal pore cap (SPC) of the Basidiomycota, are both fungal organelles that prevent cytoplasmic bleeding when multicellular hyphal filaments are wounded. Analysis of Woronin body constituent proteins suggests that these organelles evolved in part through gene duplication and co-opting of non-essential genes for new functions, indicating that new organelles can arise through typical evolutionary mechanisms. Interestingly, clades possessing the Woronin body and SPC also produce the largest and most complex multicellular fungal reproductive structures. Certain Woronin body and SPC mutants have defects in growth and development, suggesting functions beyond cellular wound healing. I argue that studying these specialized systems will help to reveal the basis for fungal diversity and provide general principles for co-evolution of organelles and multicellular complexity.
  • pH regulation and beyond: unanticipated functions for the voltage-gated proton channel, HVCN1
    - trends cell biol 21(1):20-28 (2011)
    Electrophysiological studies have implicated voltage-gated proton channels in several specific cellular contexts. In neutrophils, they mediate charge compensation that is associated with the oxidative burst of phagocytosis. Molecular characterization of the hydrogen voltage-gated channel 1 (HVCN1) has enabled identification of unanticipated and diverse functions: HVCN1 not only modulates signaling from the B-cell receptor following B-cell activation and histamine release from basophils, but also mediates pH-dependent activation of spermatozoa, as well as acid secretion by tracheal epithelium. The importance of HVCN1 in pH regulation during phagocytosis was established by surprising evidence that indicated its first-responder role. In this review, we discuss recent findings from a functional perspective, and the potential of HVCN1 as a therapeutic target for autoimmune and other diseases.
  • The Nebulin family: an actin support group
    - trends cell biol 21(1):29-37 (2011)
    Nebulin, a giant, actin-binding protein, is the largest member of a family of proteins (including N-RAP, nebulette, lasp-1 and lasp-2) that are assembled in a variety of cytoskeletal structures, and expressed in different tissues. For decades, nebulin has been thought to act as a molecular ruler, specifying the precise length of actin filaments in skeletal muscle. However, emerging evidence suggests that nebulin should not be viewed as a ruler but as an actin filament stabilizer required for length maintenance. Nebulin has also been implicated recently in an array of regulatory functions independent of its role in actin filament length regulation. In this review, we discuss the current evolutionary, biochemical, and functional data for the nebulin family of proteins — a family whose members, both large and small, function as cytoskeletal scaffolds and stabilizers.
  • Kinetochores' gripping feat: conformational wave or biased diffusion?
    - trends cell biol 21(1):38-46 (2011)
    Climbing up a cliff while the rope unravels underneath your fingers does not sound like a well-planned adventure. Yet chromosomes face a similar challenge during each cell division. Their alignment and accurate segregation depends on staying attached to the assembling and disassembling tips of microtubule fibers. This coupling is mediated by kinetochores, intricate machines that attach chromosomes to an ever-changing microtubule substrate. Two models for kinetochore-microtubule coupling were proposed a quarter century ago: conformational wave and biased diffusion. These models differ in their predictions for how coupling is performed and regulated. The availability of purified kinetochore proteins has enabled biochemical and biophysical analyses of the kinetochore-microtubule interface. Here, we discuss what these studies reveal about the contributions of each model.
  • Forcing form and function: biomechanical regulation of tumor evolution
    - trends cell biol 21(1):47-56 (2011)
    Cancer cells exist in a constantly evolving tissue microenvironment of diverse cell types within a proteinaceous extracellular matrix. As tumors evolve, the physical forces within this complex microenvironment change, with pleiotropic effects on both cell- and tissue-level behaviors. Recent work suggests that these biomechanical factors direct tissue development and modulate tissue homeostasis, and, when altered, crucially influence tumor evolution. In this review, we discuss the biomechanical regulation of cell and tissue homeostasis from the molecular, cellular and tissue levels, including how modifications of this physical dialogue could contribute to cancer etiology. Because of the broad impact of biomechanical factors on cell and tissue functions, an understanding of tumor evolution from the biomechanical perspective should improve risk assessment, clinical diagnosis and the efficacy of cancer treatment.
  • Common themes in centriole and centrosome movements
    - trends cell biol 21(1):57-66 (2011)
    Centrioles are found in nearly all eukaryotic cells and are required for growth and maintenance of the radial array of microtubules, the mitotic spindle, and cilia and flagella. Different types of microtubule structures are often required at different places in a given cell; centrioles must move around to nucleate these varied structures. Here, we draw together recent data on diverse centriole movements to decipher common themes in how centrioles move. Par proteins establish and maintain the required cellular asymmetry. The actin cytoskeleton facilitates movement of multiple basal bodies. Microtubule forces acting on the cell cortex, and nuclear–cytoskeletal links, are important for positioning individual centrosomes, and during cell division. Knowledge of these common mechanisms can inform the study of centriole movements across biology.

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