A novel physiological role for ARF1 in the formation of bidirectional tubules from the Golgi

作者：Bottanelli Francesca; Kilian Nicole; Ernst Andreas M; Rivera Molina Felix; Schroeder Lena K; Kromann Emil B; Lessard Mark D; Erdmann Roman S; Schepartz Alanna; Baddeley David; Bewersdorf Joerg; Toomre Derek; Rothman James E^*

来源：Molecular Biology of the Cell, 2017, 28(12): 1676-1687.

DOI：10.1091/mbc.E16-12-0863

Capitalizing on CRISPR/Cas9 gene-editing techniques and super-resolution nanoscopy, we explore the role of the small GTPase ARF1 in mediating transport steps at the Golgi. Besides its well-established role in generating COPI vesicles, we find that ARF1 is also involved in the formation of long (similar to 3 mu m), thin (similar to 110 nm diameter) tubular carriers. The anterograde and retrograde tubular carriers are both largely free of the classical Golgi coat proteins coatomer (COPI) and clathrin. Instead, they contain ARF1 along their entire length at a density estimated to be in the range of close packing. Experiments using a mutant form of ARF1 affecting GTP hydrolysis suggest that ARF1[GTP] is functionally required for the tubules to form. Dynamic confocal and stimulated emission depletion imaging shows that ARF1-rich tubular compartments fall into two distinct classes containing 1) anterograde cargoes and clathrin clusters or 2) retrograde cargoes and coatomer clusters.

• 出版日期2017-6-15