RT Journal Article
SR Electronic
T1 Phosphorylation of the exocyst subunit Exo70B2 contributes to the regulation of its function
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 266171
DO 10.1101/266171
A1 Ooi-Kock Teh
A1 Chil-Woo Lee
A1 Franck Aniset Ditengou
A1 Till Klecker
A1 Giulia Furlan
A1 Marco Zietz
A1 Gerd Hause
A1 Lennart Eschen-Lippold
A1 Wolfgang Hoehenwarter
A1 Justin Lee
A1 Thomas Ott
A1 Marco Trujillo
YR 2018
UL http://biorxiv.org/content/early/2018/02/19/266171.abstract
AB The exocyst is a conserved hetero-octameric complex mediating early tethering during exocytosis. Its Exo70 subunit plays a critical role as a spatiotemporal regulator by mediating numerous protein and lipid interactions. However, a molecular understanding of the exocyst function remains challenging. We show that Exo70B2 locates to dynamic foci at the plasma membrane and transits through a BFA-sensitive compartment, reflecting its canonical function in secretion. However, treatment with the salicylic acid (SA) defence hormone analogue Benzothiadiazole (BTH), or the immunogenic peptide flg22, induced Exo70B2 transport into the vacuole. We uncovered two ATG8- interacting motifs (AIMs) located in the C-terminal domain (C-domain) that mediate its recruitment into the vacuole. Moreover, we also show that Exo70B2 is phosphorylated near the AIMs and mimicking phosphorylation enhanced ATG8 interaction. Finally, Exo70B2 phosphonull lines were hypersensitive to BTH and more resistant to avirulent bacteria which induce SA production. Our results suggest a molecular mechanism in which phosphorylation of Exo70B2 by MPK3 functions in a feed-back system linking cellular signalling to the secretory pathway.