2.A.36.7.6 Dimeric Salt-Overly-Sensitive 1 (SOS1) sodium:proton exchanger 7 (NHX7) (Núñez-Ramírez et al. 2012). The salt stress-induced SOS pathway in A. thaliana involves the perception of a calcium signal by the SOS3 and SOS3-like
CALCIUM-BINDING PROTEIN8 (SCaBP8; TC# 5.B.1.1.8) calcium sensors, which then interact
with and activate the SOS2 protein kinase (9.B.106.3.4), forming a complex at the
plasma membrane that activates the SOS1 Na⁺/H⁺ exchanger (Lin et al. 2014). The involvement of SOS1 in Na+ efflux in plant roots has been reviewed (Britto and Kronzucker 2015). SOS1 appears to encode a salinity-inducible plasma membrane Na+ /H+ antiporter (Song et al. 2012). ZmSWEET1b is responsible for assimilation and salt stress response in maize. It is generally important for maize plant development and responses to salt stress (Wu et al. 2023). SOS1) is an electroneutral Na+/H+ antiporter at the plasma membrane of higher plants and plays a central role in resisting salt stress. SOS1 is kept in a resting state with basal activity and activated upon phosphorylation. Wang et al. 2023 reported structures of SOS1 which forms a homodimer, with each monomer composed of transmembrane and intracellular domains. SOS1 is locked in an occluded state by shifting of the lateral-gate TM5b toward the dimerization domain, thus shielding the Na+/H+ binding site. Ddimerization of the intracellular domain stabilizes the transporter in this conformation. Moreover, two discrete fragments and a residue W1013 are important to prevent the transition of SOS1 to an alternative conformational state. A study enhances an understanding of the alternate access model of eukaryotic Na+/H+ exchangers (Wang et al. 2023). The structure and activation mechanism of the rice SOS1 Na+/H+ antiporter has been described (Zhang et al. 2023).
|
Accession Number: | Q9LKW9 |
Protein Name: | Sodium/hydrogen exchanger 7 |
Length: | 1146 |
Molecular Weight: | 127188.00 |
Species: | Arabidopsis thaliana (Mouse-ear cress) [3702] |
Number of TMSs: | 11 |
Location1 / Topology2 / Orientation3: |
Cell membrane1 / Multi-pass membrane protein2 |
Substrate |
sodium(1+) |
---|
1: MTTVIDATMA YRFLEEATDS SSSSSSSKLE SSPVDAVLFV GMSLVLGIAS RHLLRGTRVP
61: YTVALLVIGI ALGSLEYGAK HNLGKIGHGI RIWNEIDPEL LLAVFLPALL FESSFSMEVH
121: QIKRCLGQMV LLAVPGVLIS TACLGSLVKV TFPYEWDWKT SLLLGGLLSA TDPVAVVALL
181: KELGASKKLS TIIEGESLMN DGTAIVVFQL FLKMAMGQNS DWSSIIKFLL KVALGAVGIG
241: LAFGIASVIW LKFIFNDTVI EITLTIAVSY FAYYTAQEWA GASGVLTVMT LGMFYAAFAR
301: TAFKGDSQKS LHHFWEMVAY IANTLIFILS GVVIAEGILD SDKIAYQGNS WRFLFLLYVY
361: IQLSRVVVVG VLYPLLCRFG YGLDWKESII LVWSGLRGAV ALALSLSVKQ SSGNSHISKE
421: TGTLFLFFTG GIVFLTLIVN GSTTQFVLRL LRMDILPAPK KRILEYTKYE MLNKALRAFQ
481: DLGDDEELGP ADWPTVESYI SSLKGSEGEL VHHPHNGSKI GSLDPKSLKD IRMRFLNGVQ
541: ATYWEMLDEG RISEVTANIL MQSVDEALDQ VSTTLCDWRG LKPHVNFPNY YNFLHSKVVP
601: RKLVTYFAVE RLESACYISA AFLRAHTIAR QQLYDFLGES NIGSIVINES EKEGEEAKKF
661: LEKVRSSFPQ VLRVVKTKQV TYSVLNHLLG YIENLEKVGL LEEKEIAHLH DAVQTGLKKL
721: LRNPPIVKLP KLSDMITSHP LSVALPPAFC EPLKHSKKEP MKLRGVTLYK EGSKPTGVWL
781: IFDGIVKWKS KILSNNHSLH PTFSHGSTLG LYEVLTGKPY LCDLITDSMV LCFFIDSEKI
841: LSLQSDSTID DFLWQESALV LLKLLRPQIF ESVAMQELRA LVSTESSKLT TYVTGESIEI
901: DCNSIGLLLE GFVKPVGIKE ELISSPAALS PSNGNQSFHN SSEASGIMRV SFSQQATQYI
961: VETRARAIIF NIGAFGADRT LHRRPSSLTP PRSSSSDQLQ RSFRKEHRGL MSWPENIYAK
1021: QQQEINKTTL SLSERAMQLS IFGSMVNVYR RSVSFGGIYN NKLQDNLLYK KLPLNPAQGL
1081: VSAKSESSIV TKKQLETRKH ACQLPLKGES STRQNTMVES SDEEDEDEGI VVRIDSPSKI
1141: VFRNDL