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022 _a0176-1617
040 _aMSU
_bEnglish
_cMSU
_erda
050 0 0 _aQK711.2 JOU
100 1 _aKataya, Amr. R.A.
_eauthor
245 1 0 _aMAP kinase phosphatase 1 harbors a novel PTS1 and is targeted to peroxisomes following stress treatments
_ccreated by Amr. R.A. Kataya, Edit Schei, Cathrine Lillo
264 1 _aAmsterdam:
_bElsevier GmbH,
_c2015.
336 _2rdacontent
_atext
_btxt
337 _2rdamedia
_aunmediated
_bn
338 _2rdacarrier
_avolume
_bnc
440 _aJournal of Plant Physiology
_vVolume 179
520 3 _aIn Arabidopsis thaliana, twenty mitogen-activated protein kinases (MAPKs/MPKs) are regulated by five MAP kinase phosphatases (MKPs). Arabidopsis MKP1 has an important role in biotic, abiotic and genotoxic stresses and has been shown to interact with and negatively regulate specifically MPK3 and MPK6. MKP1 has been reported to have a role in negative regulation of reactive oxygen species (ROS) and salicylic acid (SA) production. As essential organelles involved in production of ROS and SA, peroxisomes could possibly be an important compartment for MKP1 activity, however MKP1 was previously reported to be cytosolic. By screening Arabidopsis protein phosphatases for peroxisomal targeting signal 1 (PTS1), we identified MKP1 as a putative peroxisomal protein. Arabidopsis MKP1 was found to harbor a non-canonical PTS1-like tripeptide (Ser-Ala-Leu>) that is conserved in MKP1 orthologs. We show experimentally that the C-terminal Ser-Ala-Leu> can function as a novel PTS1, and alanine in position -2, adds more relaxation to the plant PTS1 motif. The full-length MKP1 remained in the cytosol when transiently expressed in Arabidopsis mesophyll protoplasts under standard conditions. When different biotic and abiotic stresses were applied to mesophyll protoplasts, the full length protein changed its targeting to unidentified organelle-like structures that subsequently fused with peroxisomes. Our results identify MKP1 as a protein dually targeted to cytosol and peroxisomes. The finding that MKP1 targets peroxisomes by a non-canonical PTS1 under stressful conditions highlights the complexity of peroxisomal targeting mechanism.
650 _aArabidopsis thaliana
650 _aMAP kinase signaling
650 _aMKP1
700 1 _aSchei, Edit
_eco-author
700 1 _aLillo, Cathrine
_eco-author
856 _uhttps://doi.org/10.1016/j.jplph.2015.03.002
942 _2lcc
_cJA
999 _c169381
_d169381