Trends in cell biology

The TACC proteins: TACC-ling microtubule dynamics and centrosome function.

Publication Date: 2008 Aug PMID: 18656360
Authors: Peset, I. - Vernos, I.
Journal: Trends Cell Biol

A major quest in cell biology is to understand the molecular mechanisms underlying the high plasticity of the microtubule network at different stages of the cell cycle, and during and after differentiation. Initial reports described the centrosomal localization of proteins possessing transforming acidic coiled-coil (TACC) domains. This discovery prompted several groups to examine the role of TACC proteins during cell division, leading to indications that they are important players in this complex process in different organisms. Here, we review the current understanding of the role of TACC proteins in the regulation of microtubule dynamics, and we highlight the complexity of centrosome function.

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Mechanisms of procentriole formation.

Publication Date: 2008 Aug PMID: 18620859
Authors: Strnad, P. - Gonczy, P.
Journal: Trends Cell Biol

The centrosome comprises a pair of centrioles and associated pericentriolar material, and it is the principal microtubule-organizing centre of most animal cells. Like the genetic material, the centrosome is duplicated once and only once during the cell cycle. Despite the fact that both doubling events are crucial for genome integrity, the understanding of the mechanisms governing centrosome duplication has lagged behind the fuller knowledge of DNA replication. Here, we review recent findings that provide important mechanistic insights into how a single procentriole forms next to each centriole once per cell cycle, thus ensuring that one centrosome becomes two.

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Using plasma membrane nanoclusters to build better signaling circuits.

Publication Date: 2008 Aug PMID: 18620858
Authors: Harding, A. S. - Hancock, J. F.
Journal: Trends Cell Biol

Cellular signaling pathways do not simply transmit data; they integrate and process signals to operate as switches, oscillators, logic gates, memory modules and many other types of control system. These complex processing capabilities enable cells to respond appropriately to the myriad of external cues that direct growth and development. The idea that crosstalk and feedback loops are used as control systems in biological signaling networks is well established. Signaling networks are also subject to exquisite spatial regulation, yet how spatial control modulates signal outputs is less well understood. Here, we explore the spatial organization of two different signal transduction circuits: receptor tyrosine kinase activation of the mitogen-activated protein kinase module; and glycosylphosphatidylinositol-anchored receptor activation of phospholipase C. With regards to these pathways, recent results have refocused attention on the crucial role of lipid rafts and plasma membrane nanodomains in signal transmission. We identify common design principals that highlight how the spatial organization of signal transduction circuits can be used as a fundamental control mechanism to modulate system outputs in vivo.

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Role of myeloid cells in tumor angiogenesis and growth.

Publication Date: 2008 Aug PMID: 18614368
Authors: Shojaei, F. - Zhong, C. - Wu, X. - Yu, L. - Ferrara, N.
Journal: Trends Cell Biol

Cells of the innate immune system have a key role in maintaining homeostasis by providing the first line of defense against many pathogens. Innate immunity can also modulate the activity of acquired immunity by several mechanisms. However, subsets of myeloid cells can facilitate tumor growth, because these cells produce angiogenic factors and can also prevent the immune system from attacking tumor cells. Recent studies also emphasize the role of myeloid cells in mediating refractoriness to anti-VEGF treatments. This function of myeloid cells occurs through a proangiogenic pathway that is, at least in part, driven by the secreted protein Bv8. This review summarizes recent findings on the complex role of bone marrow-derived cells in tumor growth.

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