Open AccessLoss of Arabidopsis p24 function affects ERD2 traffic and Golgi structure and activates the unfolded protein response
Author(s) -
Noelia Pastor-Cantizano,
César Bernat-Silvestre,
María Jesús Marcote,
Fernando Aniento
Publication year - 2017
Publication title -
journal of cell science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.384
H-Index - 278
eISSN - 1477-9137
pISSN - 0021-9533
DOI - 10.1242/jcs.203802
Subject(s) - copii , biology , golgi apparatus , copi , endoplasmic reticulum , unfolded protein response , microbiology and biotechnology , secretory pathway , mutant , secretory protein , arabidopsis , protein subunit , secretion , transport protein , chaperone (clinical) , biochemistry , gene , medicine , pathology
p24 proteins are key regulators of protein trafficking along the secretory pathway but very little is known about their functions in plants. A quadruple loss-of-function mutant affecting the p24 genes from the δ-1 subclass of the p24 delta subfamily (p24δ3δ4δ5δ6) showed alterations in the Golgi apparatus, suggesting that these p24 proteins play a role in the organization of the compartments of the early secretory pathway in Arabidopsis. Loss of p24δ-1 proteins also induced the accumulation of the K/HDEL receptor ERD2 at the Golgi apparatus and increased secretion of the ER chaperone BiP, an HDEL ligand, probably due to an inhibition of COPI-dependent Golgi-to-ER transport of ERD2 and thus retrieval of K/HDEL ligands. Although the p24δ3δ4δ5δ6 mutant showed enhanced sensitivity to salt stress, it did not show obvious phenotypic alterations under standard growth conditions. Interestingly, this mutant showed a constitutive activation of the unfolded protein response (UPR) and the up-regulation of the COPII subunit SEC31A, which may help the plant to cope with those transport defects in the absence of p24 proteins.