Let It Go

Winter pressures. Let it flow, let it flow, let it flow.

Knowing when to let go

uring meiosis I, some mechanism must allow homologous chromosomes to separate while keeping sister chromatids paired until meiosis II. How does a cell make this distinction? On page 219, Rogers et al. propose that in C. elegans the aurora-B kinase AIR-2 is largely responsible for ensuring that cohesion between chromosomes breaks down at the proper place and time. The authors also identified add...

Cohesin resolves to let go

or microtubule asters, just as with life in general, sometimes you get stuck in a corner. And, say Cendrine Faivre-Moskalenko and Marileen Dogterom (FOM Institute for Atomic and Molecular Physics, Amsterdam, Netherlands), it can take a catastrophe to get things moving again. Dogterom has been trying to reproduce aster behavior in the minimal environment of a microfabricated chamber. Her beads, ...

Crossing over to let go

A function for multisite phosphorylation Many transcription factors are regulated by phosphorylation on multiple residues. Mylona et al. analyzed multisite phosphorylation in the transcription factor Elk-1 and showed that it may protect against excessive activation (see the Perspective by Whitmarsh and Davis). Phosphorylation by the kinase ERK2 occurred at eight sites, but the sites were phosph...

Neurons let it slide

During mammalian brain development, many neurons migrate away from the site where they are born to settle in distant locations where they send out dendrites and axons to connect with other neurons. Both neuronal migration and axon/dendrite extension depend on forces generated by microtubule-based motor proteins such as cytoplasmic dynein. The effects of these forces depend, however, on the orga...