TRAPPIII requires Drs2 binding to transport Atg9 vesicles at cold temperatures

ABSTRACT

Autophagy requires a tightly controlled and adjustable subcellular distribution of Atg9. Although the machinery that regulates the transport of Atg9-positive vesicles has attracted much interest, the mechanism controlling Atg9 trafficking beyond standard laboratory conditions remains poorly understood. Recently, we demonstrated that the lipid flippase Drs2 participates in the transport of Atg9 vesicles to the phagophore assembly site, and this Drs2 function becomes necessary as temperature drops. Drs2, through an I(S/R)TTK motif nested in a conserved N-terminal cavity, binds and stabilizes the transport protein particle III (TRAPPIII) on Atg9-positive membranes. This is a new function for this lipid flippase and illustrates the necessity to investigate the mechanism of selective autophagy beyond standard laboratory conditions.

Abbreviations

Autophagy-related 9 (Atg9); cytoplasm-to-vacuole targeting (Cvt); Golgi-associated retrograde protein (GARP); multisubunit tethering complexes (MTCs); phagophore assembly site (PAS); phosphatidylserine (PS); Protein interactions from Imaging Complexes after Translocation (PICT); transport protein particle III (TRAPPIII); type IV P-type ATPases (P4-ATPases)

KEYWORDS:

• Atg9
• cytoplasm-to-vacuole targeting
• Drs2
• multisubunit tethering complex
• P4-ATPases
• TRAPPIII

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work was supported by the Agencia Estatal de Investigación [PID2021-127773NB-I00, MDM-2014-0370]; Human Frontier Science Program [RGP0017/2020].