Adhesion

TES is a novel focal adhesion protein with a role in cell spreading. Coutts, A. S. et al. J. Cell Sci. 116, 897–906 (2003)

TES was previously identified as a candidate tumour-suppressor gene. As reported here, Coutts et al. carried out yeast two-hybrid analysis and found that TES interacts with several focal adhesion and/or cytoskeletal proteins. Further studies showed TES to localize to regions of cell–substrate and cell–cell contact. Focal-adhesion-associated proteins might mediate cell adhesion, migration or cell signalling, and TES, when overexpressed, was found to confer on fibroblasts an increased ability to spread.

Development

Retraction of the Drosophila germ band requires cell–matrix interaction. Schöck, F. & Perrimon, N. Genes Dev. 17, 597–692 (2003)

The absence of integrins in Drosophila affects germ-band retraction, which involves large-scale epithelial movements. Here, α1, 2 laminin and αPS3βPS integrin were shown to be needed for a small group of cells of the amnioserosa (a squamous epithelium) to spread over the end of the germ band. In the absence of βPS integrin, lamellipodia formation was inhibited and no cell–matrix adhesion between the amnioserosa and the tail end of the germ band occurred.

Signalling

Redox-dependent downregulation of Rho by Rac. Nimnual, A. S., Taylor, L. & Bar-Sagi, D. Nature Cell Biol. 5, 236–241 (2003)

Balancing the opposing effects of Rac and Rho on the cytoskeleton is crucial for determining cell morphology and migratory behaviour. Here, the authors found that Rac, through its unique insert region, generates reactive oxygen species (ROS). A resultant decrease in Rho activity occurs through ROS-mediated inhibition of the low-molecular-weight protein tyrosine phosphatase (LMW-PTP) and subsequent activation, by increased tyrosine phosphorylation, of p190Rho-GAP, enabling Rac to induce membrane ruffling and integrin-mediated spreading.

Chromosome biology

Global chromosome positions are transmitted through mitosis in mammalian cells. Gerlich, D. et al. Cell 2003 March 4 (DOI: 10.1016/S0092867403001892)

How and when are chromosomes positioned non-randomly in mammalian cells? Gerlich et al. used non-invasive labelling and 4D imaging to show that no global chromosome rearrangements occur in interphase, G1, S or G2 of the cell cycle, but that global positioning occurs during mitosis and is transmitted from one cell generation to the next. They propose that this occurs by chromosome-specific timing of sister-chromatid separation.