Dynein branches out

Individual neurons form specific elaborate dendritic structures that receive presynaptic information. The pattern of dendritic branching is regulated by the microtubule-associated motor protein dynein, which is responsible for the transport of essential endosomes and other organelles into the dendrites.     

Ubiquitin branches out

In recent years, there has been a marked expansion of recognized roles for ubiquitin (Ub) in processes other than proteasome-dependent proteolysis, as well as a proliferation of Ub-like proteins that also function through covalent attachment to other proteins. The full diversity of functions for these proteins was on display at the American Society for Cell Biology (ASCB) meeting on "Non-Traditional Functions of Ubiquitin and Ubiquitin-Like Proteins" held at Colorado College in Colorado Springs, Colorado (August 11-14th, 2002).     

Recombination: homologous recombination branches out.

Homologous recombination can be divided into three key steps: strand exchange, branch migration and resolution. The identification of a protein complex that catalyses branch migration and Holliday junction resolution argues that the mechanism of homologous recombination is conserved from bacteria to man.     

The metabolic sensor GCN2 branches out

GCN2 is a sensor of amino acid deprivation that triggers a repression of global protein synthesis while simultaneously inducing translation of specific proteins. In this issue of Cell Metabolism, Guo and Cavener (2007) present a much broader role for GCN2 in controlling lipid homeostasis in response to amino acid deprivation.     

Plant genomics takes root, branches out

For the past nine years, an international consortium of researchers have collaborated on a project to provide a full set of genomics tools for the model plant species Arabidopsis thaliana. Among the goals of this project were the complete sequence of the Arabidopsis genome, which may be completed in the year 2000, four years ahead of schedule. Arabidopsis was an appropriate choice as the first target of plant genomics because of its excellent genetics, outstanding research community and small genome size. Until very recently, it appeared that comprehensive high-throughput plant genomics in the public sector would largely begin and end with Arabidopsis. Over the past two years, this situation has changed completely.     

Polycomb in stem cells: PRC1 branches out

Polycomb group proteins (PcGs) generate chromatin-modifying complexes that regulate gene expression. PcGs are categorized into two major groups, polycomb repressive complex 1 (PRC1) and 2 (PRC2), which have classically been thought to function together. Here we discuss recent data challenging this model indicating that the distinct subunit composition of PRC1 confers specific and nonoverlapping functions in embryonic and adult stem cells.