Actin branches out in yeast

Many of the same proteins control actin polymerization in budding yeast and mammalian cells. But budding yeast researchers—hampered by an emphasis on genetics and an inaccessible yeast cytoplasm dense with ribosomes and glycogen granules—have often lagged behind in providing structural descriptions based on electron microscopy (EM). This has fueled suspicions about whether the study of yeast actin is relevant to human systems.

Now, Young et al. (page 629) get the structural ball rolling with an EM characterization of yeast cortical actin patches, which are the most prominent actin structures in budding yeast. They find significant structural parallels between the yeast and mammalian systems, suggesting that the smaller yeast structures may be a handy model for tackling problems of actin dynamics.

The team partially purified patches from cells expressing GFP-labeled capping protein. Once...