TRANSIT ZONE. EXIT GATE № 2020-2021

No exit for Ca2+

Diet affects DNA itochondria apparently adjust their DNA inheritance stategies when faced with different metabolic conditions, based on results from Xin Jie Chen, Ronald Butow, and colleagues (UTSW, Dallas, TX). The key to the change is a metabolic protein called aconitase. When grown in glucose, budding yeast rely on glycolytic fermentation, but on other carbon sources the Krebs cycle and oxid...

Cell Biology: Cohesin Ring Exit Gate Revealed

A multiprotein complex called cohesin mediates sister chromatid cohesion by entrapping sister DNAs into a tripartite ring. Recent studies show that Wapl opens the newly identified DNA exit gate of the cohesin ring, only when Smc3 is deacetylated, and that mutations in human Smc3 deacetylase cause a developmental disorder.

No exit strategy for lipids

Lipids heading toward lysosomes that carry a mutated ion channel are spared from destruction, according to Meidel et al. (page 1477). The accumulating undigested fat eventually dooms the cell. Cells get rid of excess fat, which comes from worn-out organelles or engulfed pathogens by, for instance, shuttling them in endosomes to degradative lysosomes. The two organelles are thought to fuse when ...

cover Vol.17- No.1 February 2020

The Ribosomal Exit Tunnel Functions as a Discriminating Gate

Translation of SecM stalls unless its N-terminal part is "pulled" by the protein export machinery. Here we show that the sequence motif FXXXXWIXXXXGIRAGP that includes a specific arrest point (Pro) causes elongation arrest within the ribosome. Mutations that bypass the elongation arrest were isolated in 23S rRNA and L22 r protein. Such suppressor mutations occurred at a few specific residues of...