Time for a quick roundup of some of the highlights from today’s new issue of JCB. First up, Titos et al. describe how the topological constraints imposed by chromosome length and attachment to the nuclear envelope make it more difficult for topoisomerase II resolve intertwined sister chromatids during anaphase. As explained in this week’s In Focus, the researchers also uncover a role for dynamic microtubules in the process.
Staying with cell division, Elsing et al. reveal that a temporary decrease in expression of the transcription factor HSF2 during mitosis allows some cell types to produce heat shock proteins that can protect mitotic cells from environmental stess. More here.
Saito et al. describe how ER exit sites manage to export large collagen molecules to the Golgi apparatus. As described here, the researchers show that, in the ER, the collagen cargo receptor cTAGE5 recruits large amounts of Sec12, a guanine nucleotide exchange factor that stimulates assembly of the COPII vesicle coat that mediates collagen transport.
And Shen et al. reveal how a key component of the membrane-snipping ESCRT-III complex gets in shape. The ESCRT-III complex cuts membranes during processes such as cell division and viral budding. As summarized here, Shen et al. describe how the ESCRT-III subunit Vps32 assembles into tightly coiled filaments, a configuration that serve to store energy that can subsequently be released to sever cellular membranes.
Meanwhile, in this month’s biobytes podcast, Dipal Patel discusses how disease-associated mutations in the desmosomal protein desmoplakin affect microtubule dynamics and gap junction assembly (Patel et al.), and Julia von Blume explains how the actin-severing protein cofilin regulates a calcium pump to control protein sorting at the trans-Golgi network (Kienzle et al.). You can listen below or subscribe in iTunes.
That’s all we have time for this week, but there are plenty of other interesting papers to discover on our table of contents page here. Let us know if I didn’t mention your favorite!
Cover image of Vps32 filaments © 2014 Shen et al.