Volume 12 Issue 8, August 2011

Phosphorylation of ATF2 leads to heritable disruption of heterochromatin.

Describes the discovery of the NoCut checkpoint.

Identifies the long sought-after mitochondrial calcium uniporter.

A chain initiation motif in APC/C substrates regulates the timing of degradation.

MIEF1 is identified as a novel regulator of mitochondrial membrane dynamics.

SH3BP1 interacts with the exocyst to inactivate RAC1 at the leading edge.

FBXW5 regulates centrosome duplication and is itself controlled by APC/C and PLK4.

Replicative lifespan is reset during gametogenesis in budding yeast.

The regulation of mitotic exit requires the rapid reversal of mitotic phosphorylation on a broad range of substrates. This requires not only inactivation of mitotic kinases but also activation of protein phosphatases, which work in regulatory networks to ensure that an interphase cell is correctly established.

In eukaryotes, RNA polymerases I, II and III synthesize RNAs, which are essential for life. Remarkably, plants have evolved two additional multisubunit RNA polymerases, RNA polymerases IV and V, to orchestrate non-coding RNA-mediated gene silencing processes. Their subunit compositions reveal that they evolved as specialized forms of RNA polymerase II.

RHO-specific guanine nucleotide dissociation inhibitors (RHOGDIs) had long been considered to be passive inhibitors of RHO GTPases, 'locking' them in an inactive state. However, recent findings suggest that they have integral roles in regulating RHO GTPases, controlling aspects such as stability, expression, activity and membrane localization.

RNA helicases of the DEAD box family are highly conserved enzymes with many roles in gene expression. Structural and mechanistic studies are uncovering the basis of their actions and have revealed roles not only in RNA unwinding but also in the remodelling of RNA–protein complexes and in the clamping of RNA to allow nucleation of larger complexes.

Clathrin-mediated endocytosis is a modular process that involves core and accessory adaptor proteins that package cargoes into vesicles, ultimately leading to their uptake. It is essential for many physiological processes in higher eukaryotes, including signal termination and exocytosis, so its components are rarely associated with disease.

This timeline article pays tribute to the late James Fred 'Paulo' Dice, whose vision of selective protein degradation in lysosomes led to the discovery of chaperone-mediated autophagy.