title: Salt stress signaling in Arabidopsis thaliana involves a membrane-bound transcription factor AtbZIP17 as a signal transducer.
abstract: Plants have developed robust signaling mechanisms to cope with environmental stresses. In a recent article in the Plant Journal,1 we reported on a salt stress signaling pathway in Arabidopsis, which is mechanically similar to endoplasmic reticulum (ER) stress responses described in mammalian systems. We found that a type II membrane-bound transcription factor (AtbZIP17) is a salt stress signal transducer and a subtilisin-like serine protease (AtS1P) is a key component of the protein processing machinery in the signaling pathway. AtbZIP17 is normally located in the ER, but in response to salt stress, the membrane-bound transcription factor is proteolytically processed in an AtS1P-dependent step, and the cytosolic component of AtbZIP17 is translocated to the nucleus. We have demonstrated in an in vitro assay that AtS1P directly cleaves AtbZIP17, an initial step in processing. Our study also identified several downstream target genes in the salt signaling pathway. In this addendum, we propose a testable model to describe the action of AtS1P and AtbZIP17 in salt stress signaling and we also present an outlook for future work to test this model.
authors.affiliation: Plant Sciences Institute; Roy J. Carver Co-Laboratory; Iowa State University; Ames, Iowa USA.
authors.forename: Jian-Xiang
authors.initials: JX
authors.lastname: Liu
authors.forename: Renu
authors.initials: R
authors.lastname: Srivastava
authors.forename: Ping
authors.initials: P
authors.lastname: Che
authors.forename: Stephen H
authors.initials: SH
authors.lastname: Howell
references.citation: Plant J. 1996 Aug;10(2):375-81
references.pmid: 8771791
references.citation: Mol Cell. 2000 Dec;6(6):1355-64
references.pmid: 11163209
references.citation: Annu Rev Biochem. 2005;74:739-89
references.pmid: 15952902
references.citation: J Exp Bot. 2004 Jan;55(395):225-36
references.pmid: 14673035
references.citation: Cell. 2006 Jan 13;124(1):35-46
references.pmid: 16413480
references.citation: Dev Cell. 2002 Jul;3(1):99-111
references.pmid: 12110171
references.citation: Plant J. 2007 Sep;51(5):897-909
references.pmid: 17662035
references.citation: Science. 1986 Apr 4;232(4746):34-47
references.pmid: 3513311
references.citation: Cell. 2002 Aug 23;110(4):489-500
references.pmid: 12202038
references.citation: Mol Biol Cell. 1999 Nov;10(11):3787-99
references.pmid: 10564271
references.citation: Trends Cell Biol. 2004 Jan;14(1):20-8
references.pmid: 14729177