Opinion: ATG8 expansion as a driver of selective diversification of autophagy? ($)

Autophagy is a process of selective membrane trafficking that delivers cargo to the vacuole or plasma membrane for recycling or secretion. ATG8 is a small ubiquitin-like protein that is required for formation of the double-membrane enclosed autophagy vesicle, the autophagosome. The ATG8 gene family has expanded greatly in plants, from one gene in algae to as many as 22 in some angiosperms. Kellner et al. examined the diversity of ATG8 proteins in plants and found that there are distinct ATG8 clades that are unique to particular plant families. The functional significance of this ATG8 diversification remains to be determined, but the authors suggest that different ATG8 isoforms may selectively interact with different protein targets and contribute to different autophagy-mediated processes. Trends Plant Sci. 10.1016/j.tplants.2016.11.015