A functional study of AUXILIN-LIKE1 and 2, two putative clathrin uncoating factors in Arabidopsis (Plant Cell)

Trafficking within a cell can occur through clathrin-mediated endocytosis (CME). CME depends upon coating plasma membrane vesicles with clathrin and adaptor proteins but the mechanism is unclear in plants. Adamowski et al. establish a means with which to study this process in order to further elucidate the machinery involved in plant endocytosis. Proteins involved in CME were identified by Tandem Affinity Purification (TAP), utilizing the clathrin light chain as a protein interactor, in collaboration with Mass Spectrometry. Among the identified proteins were two homologous proteins named AUXILIN-LIKE1 and AUXILIN-LIKE2, so called due to being identical to the auxilin-like protein which has been described as a putative uncoating factor in Arabidopsis. Both proteins localize to the plasma membrane (PM) and the cell plate. The authors created inducible-overexpression lines with these proteins, which resulted in inhibition of endocytosis, increase in vacuolar volume, and appeared to result in loss of clathrin specifically from the PM pool. On the other hand, auxin-like1/2 mutants did not appear to exhibit any defects. This study highlights several important tools that can be used to study CME and adds additional interactors in this process. (Summary by Alecia Biel) Plant Cell. 10.1105/tpc.17.00785