Volume 6 Issue 6, June 2004
Organelle identity and the organization of membrane traffic
Generating and maintaining features that distinguish one organelle from another is essential for accurate membrane traffic. Recent work has revealed that organelles express 'identity' by the local generation of activated GTP-binding proteins and lipid species. These recruiting determinants are then recognized by cytosolic proteins that facilitate the formation and delivery of vesicles at the correct compartment.
News & Views
Cdc14 phosphatase resolves the rDNA segregation delay
Sister chromatid segregation in anaphase of mitosis is initiated through cleavage of cohesin by the protease separase. Two studies now show that this view is valid for most chromosomal DNA, but not for the highly repetitive ribosomal DNA (rDNA) and telomeres. The disjunction of these regions of the chromosome occurs in mid-anaphase, long after cohesin cleavage, and is regulated by the conserved phosphatase Cdc14.
Fusion has found its calcium sensor
Synaptic vesicle exocytosis, a finely tuned process that results in rapid neurotransmitter release, is still not fully understood. Studies in a simple reconstituted lipid bilayer system have now definitively demonstrated that synaptotagmin has a key role in calcium-mediated exocytosis and have also revealed additional aspects of exocytic fusion.
Hsp90 invades the outside
Metalloproteases are required for the invasive nature of cancer cells. Surprisingly, the cytosolic molecular chaperone Hsp90 is now shown to promote maturation of the extracellular metalloprotease MMP2. This finding extends the multiplicity of roles assigned to the Hsp90 family to a new function outside the cell.
News & Views
Focus on membrane traffic
This section contains all material on the topic of membrane traffic published in Nature Cell Biology to date including original research papers, Reviews, Perspectives, Commentaries and News and Views. View the current focus issue from June 2004, and an earlier focus issue from October 1999.