Volume 13 Issue 1, January 2012

Lyn senses H₂O₂at wound sites and mediates neutrophil migration.

MCRS1 stabilizes K-fibres and spindle assembly in a RAN·GTP-dependent manner.

Two studies reveal roles for B-type lamins in organogenesis and cell proliferation.

Structural insight into the DKK1-mediated inhibition of WNT signalling.

PINK1 phosphorylates MIRO; parkin then degrades MIRO to halt mitochondrial movement.

Epidermal stem cell activity is directly regulated by core clock proteins.

Discusses recent papers on the topography of the interphase chromatin fibre.

A new method for high-resolution imaging using a standard wide-field microscope.

The autophagosome, the central organelle in macroautophagy, is constructed from a membrane template called the phagophore, to which autophagy-related (ATG) proteins are hierarchically recruited. Recent findings suggest that non-canonical autophagy may also occur in the absence of these key autophagy proteins.

Cells use molecular motors to position and segregate organelles. Recent studies show that class V myosins function as actin-based cargo transporters in yeast, moving the vacuole, peroxisomes and secretory vesicles. There is also increasing evidence in vertebrate cells that class V myosins can serve as short-range, point-to-point organelle transporters rather than just tethering organelles to actin.

Bone homeostasis depends on the opposing activities of osteoblasts (which form bone) and osteoclasts (which destroy bone). Recent studies have revealed the transcription factors (for example, RUNX2 and osterix) and developmental signalling pathways (including WNT and Notch signalling) that regulate the differentiation and function of osteoblasts.

RAS proteins are monomeric GTPases that act as binary molecular switches to regulate a wide range of cellular processes. Their trafficking and activity are regulated by constitutive post-translational modifications (PTMs), including farnesylation, methylation and palmitoylation, as well as conditional PTMs, such as phosphorylation, peptidyl-proly isomerization, ubiquitylation, nitrosylation, ADP ribosylation and glucosylation.

Although the multivesicular body (MVB) is classically defined as an intermediate that delivers material for lysosomal degradation, its role in the sequestration of glycogen synthase kinase 3 during WNT signalling has revealed a positive influence of this organelle in signalling control. This Opinion article proposes that this function of MVBs as a signalling organelle is physiologically relevant during development and may be common to diverse signalling pathways.