This week in PLOS Biology

In PLOS Biology this week, you can read about a molecule with the potential to treat malaria, the remarkable diversity in sex determination and regulation of synaptic homeostasis.

Malaria is a mosquito-borne infectious disease which in 2010 killed up to 1.2 million people. The parasites that cause malaria live inside red blood cells, and while there secrete many different proteins that mold the host cells to their own purposes. An enzyme called Plasmepsin V is known to be involved in the correct secretion of these proteins. In new research, Brad Sleebs, Justin Boddey and colleagues showed that Plasmepsin V is essential for malarial parasite survival, and were able to design a molecule which could inhibit its activity. Although this molecule was needed at too high a concentration for it to be useful clinically, future refinements could lead to a useful drug. Read more in the accompanying synopsis.

Sex determination – isn’t it mostly about X and Y? This is one of several commonly held myths debunked by Doris Bachtrog, Jana Vamosi and co-authors in a new addition to our ‘Unsolved Mystery’ series. The authors discuss the myriad different mechanisms by which sex has evolved to be determined in eukaryotes. They survey our current understanding of the topic and identify important knowledge gaps.

Negative feedback is an important mechanism across many systems. One example is in the dampening down of excessive activity in neurons. New research by Seonil Kim and Edward Ziff highlights the importance of the calcium-dependent phosphatase calcineurin. Calcineurin activity is decreased when inhibition of neuronal excitability reduces calcium influx. This leads in turn to increased levels of phosphorylation and resulting stabilisation of AMPA receptors – a type of glutamate receptor that’s permeable to calcium, thereby closing the feedback loop.