Mitosis: Don't get mad, get even

The ‘mitotic spindle checkpoint’ ensures that, before a cell exits from mitosis, all of its chromosomes are aligned on the spindle to form the metaphase plate. Mad2 is an essential component of this checkpoint system and it binds specifically to unattached kinetochores.     

Learning to get along despite struggling to get by

How cooperation can evolve by natural selection is important for understanding the evolutionary transition from unicellular to multicellular life. Here we review the evolutionary theories for cooperation, with emphasis on the mechanisms that can favor cooperation and reduce conflict in multicellular organisms.     

Cool hamsters get sleepy

The relationship between sleep and natural hypothermic states, like daily torpor and hibernation, has always been of interest for sleep researchers. The three states were long considered functionally homologous. However, while investigating the effects of daily torpor on sleep in the Djungarian hamster (Phodopus sungorus), the results suggested that the animals are sleep deprived during hypothermia, and can only recover this sleep debt after return to euthermia. The data indicate that an important function of sleep cannot be fulfilled during the torpid state, a finding which may give additional insights into the processes involved in sleep regulation.     

Stressed-out mitochondria get MAD

Mechanisms maintaining mitochondrial integrity range from specific repair pathways to wholesale degradation of damaged organelles. A recent study in Molecular Cell (Heo et?al., 2010) adds another mechanism to this mitochondrial homeostasis toolkit: mitochondria-associated protein degradation (MAD) that ultimately directs endoplasmic reticulum-associated protein degradation (ERAD) pathway components to oxidatively stressed mitochondria.     

When sparks get old

Sparks are transient local elevations of Ca ion concentration observed in different types of muscle cells. Such local Ca2+ signals can be provoked in skeletal muscle cells by altering the osmotic pressure of the extracellular solution. In this issue, Weisleder et al. (see p. 639) demonstrate that the Ca2+ response to osmotic stress is substantially altered in aged muscle. The study presents evidence for a link between this finding and a reduced expression of mitsugumin 29 (MG29), a small membrane protein of the sarcoplasmic reticulum (SR).