| TCID | Name | Domain | Kingdom/Phylum | Protein(s) |
|---|---|---|---|---|
|
1.A.11.1.1 | Ammonia transporter and regulatory sensor, AmtB (Blauwkamp and Ninfa, 2003; Khademi et al., 2004). It has a cleavable N-terminal signal peptide, and while Amt proteins in Gram-negative bacteria appear to utilize a signal peptide, the homologous proteins in Gram-positive organisms do not (Thornton et al. 2006). | Bacteria |
Pseudomonadota | AmtB of E. coli (P69681) |
|
1.A.11.1.2 | High affinity ammonia/methylammonia uptake carrier, Amt1 or AmtA (Walter et al., 2008) | Bacteria |
Actinomycetota | Amt1 of Corynebacterium glutamicum (P54146) |
|
1.A.11.1.3 | Low affinity (KM > 3mM) ammonia uptake carrier, AmtB (Walter et al., 2008) | Bacteria |
Actinomycetota | AmtB of Corynebacterium glutamicum (Q79VF1) |
|
1.A.11.1.4 | Ammonia channel protein, AmtB (forms a ternary complex with the trimeric PII protein, GlnZ (AAG10012) and the nitrogenous regulatory glycohydrolase enzyme, DraG, causing DraG sequestration and N2ase regulation (Huergo et al., 2007) | Bacteria |
Pseudomonadota | AmtB of Azospirillum brasilense (P70731) |
|
1.A.11.1.5 | Ammonia channel (Ammonia transporter) | Bacteria |
Aquificota | Amt of Aquifex aeolicus |
|
1.A.11.1.6 | Trimeric ammonia channel protein, Amt-1 (391 aas) | Archaea |
Euryarchaeota | Amt-1 of Archaeoglobus fulgidus (O29285) |
|
1.A.11.1.7 | The ammonium transporter channel, AmtA (regulates NH3 homeostasis during growth and development (Yoshino et al., 2007). | Eukaryota |
Evosea | AmtA of Dictyostelium discoideum (Q9BLG4)
|
|
1.A.11.1.8 | AMT of 514 aas and 11 TMSs. Trypanosoma cruzi, the etiologic agent of Chagas disease, undergoes drastic metabolic changes when it transits between a vector and mammalian hosts. Amino acid catabolism leads to the production of NH4+, which must be detoxified. Cruz-Bustos et al. 2018 identified an intracellular ammonium transporter of T. cruzi (TcAMT) that localizes to acidic compartments (reservosomes, lysosomes). TcAMT possesses all conserved and functionally important residues that form the pore in other ammonium transporters. Functional expression in Xenopus oocytes followed by a two-electrode voltage clamp showed an inward current that is NH4+ dependent at a resting membrane potential lower than -120 mV and is not pH dependent, suggesting that TcAMT is an NH4+or NH3/H+ transporter. Ablation of TcAMT resulted in defects in epimastigote and amastigote replication, differentiation, and resistance to starvation and osmotic stress (Cruz-Bustos et al. 2018). | Eukaryota |
Euglenozoa | Amt of Trypanosoma cruzi |
|
1.A.11.1.9 | Ammonium transporter, NrgA, of 411 aas and 11 TMSs. The nrgA gene is co-transcribed with the glnB gene, and may play a role in molecular export and biofilm formation (Ardin et al. 2014). | Bacteria |
Bacillota | NrgA of Streptococcus mutans |
|
1.A.11.1.10 | AmtB1 of 403 aas and 11 (or 12) TMSs. | Bacteria |
Pseudomonadota | AmtB1 of Stutzerimonas stutzeri (Pseudomonas stutzeri) |
|
1.A.11.2.1 | High-affinity electrogenic ammonia/methylammonia transporter (allosterically activated by the C-terminus (Loqué et al., 2009). NH4+ is stable in the AmtB pore, reaching a binding site from which it can spontaneously transfer a proton to a pore-lining histidine residue (His168). The substrate diffuses down the pore in the form of NH3, while the proton is cotransported through a highly conserved hydrogen-bonded His168-His318 pair (Wang et al. 2012). | Eukaryota |
Viridiplantae, Streptophyta | Amt1 of Arabidopsis thaliana (P54144) |
|
1.A.11.2.2 | Ammonia-specific uptake carrier, Amt2. For AMT2 from Arabidopsis thaliana NH4+ is the recruited substrate, but the uncharged form NH3 is conducted. AtAMT2 partially co-localizes with electrogenic AMTs and conducts methylamine with low affinity (Neuhäuser et al., 2009). This may explain the different capacities of AMTs to accumulate ammonium in the plant cell. | Eukaryota |
Viridiplantae, Streptophyta | Amt2 of Arabidopsis thaliana |
|
1.A.11.2.3 | High-affinity ammonia/methylammonia transporter, Amt1(Paz-Yepes et al., 2007) | Bacteria |
Cyanobacteriota | Amt1 of Synechococcus elongatus sp. PCC7942 (Q93IP6) |
|
1.A.11.2.4 | High-affinity ammonia/methylammonia transporter, LeAMT1;1. The ammonium transporter 1 (AMT1) gene family in tomato (Solanum lycopersicum L.) and individual members of the family exhibit different physiological and expression patterns under drought and salt stress conditions (Filiz and Akbudak 2020). | Eukaryota |
Viridiplantae, Streptophyta | LeAMT1;1 of Lycopersicon esculentum (P58905) |
|
1.A.11.2.5 | Ammonium/methyl ammonium uptake permease, AmtB (may need AmtB to concentrate [14C]methyl ammonium (Paz-Yepes et al., 2007)) | Bacteria |
Cyanobacteriota | AmtB of Synechococcus sp CC9311 (Q0IDE4) |
|
1.A.11.2.6 | Pollen-specific, plasma membrane, high affinity (17μM) ammonium uptake transporter, Amt1;4 (Yuan et al., 2009) (most similar to 1.A.11.2.1). | Eukaryota |
Viridiplantae, Streptophyta | Amt1;4 of Arabidopsis thaliana (Q9SVT8) |
|
1.A.11.2.7 | Amt2 NH4+/CH3-NH3+ transporter, subject to allosteric activation by a C-terminal region (Loqué et al., 2009). | Archaea |
Euryarchaeota | Amt2 of Archaeoglobus fulgidus (O28528) |
|
1.A.11.2.8 | Amt1;1, a proposed NH4+:H+ sumporter (Ortiz-Ramirez et al., 2011) | Eukaryota |
Viridiplantae, Streptophyta | Amt1;1 of Phaseolus vulgaris (E2CWJ2) |
|
1.A.11.2.9 | Eukaryota |
Evosea | AmtB of Dictyostelium discoideum | |
|
1.A.11.2.10 | Putative ammonium transporter 2 | Eukaryota |
Metazoa, Nematoda | amt-2 of Caenorhabditis elegans |
|
1.A.11.2.11 | Ammonium transporter, AmtB or Amt1 of 463 aas and 9 TMSs. Regulated by direct interaction with GlnK (Pedro-Roig et al. 2013). | Archaea |
Euryarchaeota | AmtB of Haloferax mediterranei (Halobacterium mediterranei) |
|
1.A.11.2.12 | Ammonium uptake transporter, Amt1 of 458 aas and 11 TMSs. 62% identical to Amt1 of Pyropia yezoensis (Rhodophyta) which is 483 aas long with 11 TMSs and is induced by nitrogen deficiency (Kakinuma et al. 2016). | Eukaryota |
Rhodophyta | Amt1 of Chondrus crispus (Carrageen Irish moss) (Polymorpha crispa) |
|
1.A.11.2.13 | High affinity (~50 mμM) ammonium transporter, Amt1.3 of 498 aas and 10 TMSs (Loqué et al. 2006). The tobacco orthologue, of 464 aas and 10 TMSs, NtAMT1.3, is present in roots and leaves and faciltates NH4+ entry. It is up regulated upon nitrogen starvation (Fan et al. 2017). | Viridiplantae, Streptophyta | Ant1.3 of Arabidopsis thaliana (Mouse-ear cress) | |
|
1.A.11.2.14 | Putative ammonia/ammonium transporter of 439 aas and 11 TMSs. | Viruses |
Bamfordvirae, Nucleocytoviricota | NH3 transporter of Ostreococcus tauri virus RT-2011 |
|
1.A.11.2.15 | Ammonium transporter 3 of 506 aas and 11 TMSs. Symbiotic cnidarians such as corals and anemones form highly productive and biodiverse coral reef ecosystems in nutrient-poor ocean environments, a phenomenon known as Darwin's paradox (Cui et al. 2023). Using the sea anemone Aiptasia, we show that during symbiosis, the increased availability of glucose and the presence of the algae jointly induce the coordinated up-regulation and relocalization of glucose and ammonium transporters. These molecular responses are critical to support symbiont functioning and organism-wide nitrogen assimilation through glutamine synthetase/glutamate synthase-mediated amino acid biosynthesis (Cui et al. 2023). | Eukaryota |
Metazoa, Cnidaria | Amt of Exaiptasia diaphana |
|
1.A.11.3.1 | Low-affinity ammonia transporter, Mep1 (Has a pair of conserved his/glu residues; Boeckstaens et al., 2008) | Eukaryota |
Fungi, Ascomycota | Mep1 of Saccharomyces cerevisiae (P40260) |
|
1.A.11.3.2 | High-affinity ammonia transporter and sensor, Mep2 (also an NH4+ sensor) (Javelle et al., 2003a; Rutherford et al., 2008) (has a pair of conserved his/his residues; mutation to his/glu as in Mep1 leads to uncoupling of transport and sensor functions (Boeckstaens et al., 2008)) | Eukaryota |
Fungi, Ascomycota | Mep2 of Saccharomyces cerevisiae (P41948) |
|
1.A.11.3.3 | High affinity ammonia/methylamine transporter, Amt1 (may also serve as a sensor) (Javelle et al., 2003b) | Eukaryota |
Fungi, Basidiomycota | Amt1 of Hebeloma cylindrosporum (Q8NKD5) |
|
1.A.11.3.4 | Low affinity ammonia transporter, Amt2 (Javelle et al., 2001, 2003b) | Eukaryota |
Fungi, Basidiomycota | Amt2 of Hebeloma cylindrosporum (Q96UY0) |
|
1.A.11.3.5 | The Mep2 ammonium transporter 60% identical to the S. cerevisiae Mep2 (1.A.11.3.2). (Distinct residues mediate transport and signaling; Dabas et al., 2009). | Eukaryota |
Fungi, Ascomycota | Mep2 of Candida albicans (Q59UP8) |
|
1.A.11.4.1 | Rhesus (Rh) type C glycoprotein NH3/NH4+ transporter, RhCG (also called tumor-related protein DRC2) (Bakouh et al., 2004; Worrell et al., 2007). Zidi-Yahiaoui et al. (2009) have described characteristics of the pore/vestibule. The structure is known to 2.1 Å resolution (Gruswitz et al., 2010). Each monomer contains 12 transmembrane helices, one more than in the bacterial homologs. Reconstituted into proteoliposomes, RhCG conducts NH3 to raise the internal pH. Models of the erythrocyte Rh complex based on the RhCG structure suggest that the erythrocytic Rh complex is composed of stochastically assembled heterotrimers of RhAG, RhD, and RhCE (Gruswitz et al., 2010). Rh proteins also transport CO2 (Michenkova et al. 2021). | Eukaryota |
Metazoa, Chordata | RhCG of Homo sapiens (Q9UBD6) |
|
1.A.11.4.2 | Rhesus (Rh) type B glycoprotein NH3/NH4+ transporter, RhBG (~50% identical to type C) (Lopez et al., 2005; Worrell et al., 2008). Electrogenic NH4+ transport is stimulated by alkaline pH(out) but inhibited by acidic pH(out) (Nakhoul et al., 2010). It is regulated by Wnt/β-catenin signalling, a pathway frequently deregulated in many cancers and associated with tumorigenesis (Merhi et al. 2015). Rh proteins also transport CO2 (Michenkova et al. 2021). Rhesus blood group-associated B glycoprotein (RhBG) initiates downstream signaling and functional responses by activating NFκB (Mishra et al. 2024). RhBG interacts with myeloid differentiation primary response-88 (MyD88) to initiate an intracellular signaling cascade that culminates in activation of NFκB (Mishra et al. 2024). The conserved cytosolic J-domain of the RhBG protein interacts with the Toll-interleukin-1 receptor (TIR) domain of MyD88. Decoupling transport and signaling functions apparently occurs. | Eukaryota |
Metazoa, Chordata | RhBG of Homo sapiens (Q9H310) |
|
1.A.11.4.3 | Rhesus (Rh) complex (tetramer: RhAG2, RhCE1, RhD1) of 409 aas and 12 TMSs. Exports ammonia from human red blood cells (Conroy et al., 2005). RhAG is also called RH50. RhAG variants (I61R, F65S), associated with overhydrated hereditary stomatocytosis (OHSt), a disease affecting erythrocytes, are alterred for bidirectional ammonium transport (Deschuyteneer et al. 2013). The system transports ammonia, methylammonia, ethylammonia, fluoroethylamine and CO2 Michenkova et al. 2021. 19F-fluoroethylamine has been used to study rapid transport as its NMR spectra are different inside and outside of human red blook cells (Szekely et al. 2006). | Eukaryota |
Metazoa, Chordata | The RhAG/RhCE/RhD, complex of Homo sapiens RhAG (Q02094) RhCE (P18577) RhD (Q02161) |
|
1.A.11.4.4 | The RH50 NH3 channel (most like human Rh proteins TC# 1.A.11.4.1 and 2; 36-38% identity) (Cherif-Zahar et al., 2007). The Rh CO2 channel protein (3-D structure ± CO2 available) (3B9Z_A; 3B9Y_A) (Li et al., 2007; Lupo et al., 2007) (also transports methyl ammonia) (Weidinger et al., 2007). | Bacteria |
Pseudomonadota | RH50 of Nitrosomonas europaea (Q82X47)
|
|
1.A.11.4.5 | Kidney rhesus glycoprotein p2 (Rhp 2). Transports NH3, methylammonium and CO2 (Nakada et al., 2010; Michenkova et al. 2021). | Eukaryota |
Metazoa, Chordata | Rhp2 of Triakis scyllium (D0VX38) |
|
1.A.11.4.6 | Rhesus-like glycoprotein A (Rh50-like protein RhgA). Transports NH3 and CO2 (Michenkova et al. 2021). | Eukaryota |
Evosea | RhgA of Dictyostelium discoideum |
|
1.A.11.4.7 | Ammonium/ammonia/CO2 transporter of 391 aas and 12 TMSs (Michenkova et al. 2021). Shows limited seqences similarity with 9.B.124.1.7 (e-5) (residues 1-5 align with residues 4 - 8 in 9.B.124.1.7). | Bacteria |
Bacillota | Ammonium transporter of [Clostridium] papyrosolvens |
|
1.A.11.4.8 | NH3 (NH4+) and CO2 transporting Rhesus glycoprotein, Rhag, of 437 aas and 11 TMSs. Induced by ammonia exposure in the apical membrane of gill epithelia (Chen et al. 2017). | Eukaryota |
Metazoa, Chordata | Rhag of Anabas testudineus (climbing perch) |
|
1.A.11.4.9 | NH3 (NH4+)/CO2 transporting Rhesus glycoprotein, Rhcg2, of 482 aas and 11 TMSs. Induced by ammonia exposure in the basolateral membrane of gill epithelia (Chen et al. 2017; Michenkova et al. 2021). | Bacteria |
Metazoa, Chordata | Rhcg2 of Anabas testudineus (climbing perch) |
|
1.A.11.4.10 | RH (Rhesus) antigen-related protein, Rhr-1 or Rh1, of 463 aas and 12 TMSs. CeRh1 is abundantly expressed in all developmental stages of C. elegans, with highest levels in adults, whereas CeRh2 shows a differential and much lower expression pattern. It is required for passage throung the late stages of C. elegans embryonic development and hypodermal function (Ji et al. 2006). Transports NH3, NH4+ and CO2 (Michenkova et al. 2021).
| Eukaryota |
Metazoa, Nematoda | Rhr-1 of Caenorhabditis elegans |
|
1.A.11.4.11 | Rh protein of 478 aas and 11 TMSs. It is a primary contributor to ammonia/ammonium ions and CO2 excretion (Michenkova et al. 2021), and poor expression changes the expression levels of many enzymes (Si et al. 2018). | Eukaryota |
Metazoa, Arthropoda | Rh protein of Portunus trituberculatus (the swimming crab) |
|
1.A.11.4.12 | The rhesus protein, Rhp1, of 479 aas and 11 TMSs. Reef-building corals maintain an intracellular photosymbiotic association with dinoflagellate algae. As the algae are hosted inside the symbiosome, all metabolic exchanges must take place across the symbiosome membrane. Thies et al. 2022 established that Acropora yongei Rh (ayRhp1) facilitates transmembrane NH3 and CO2 diffusion, and that it is present in the symbiosome membrane. Furthermore, ayRhp1 abundance in the symbiosome membrane was highest around midday and lowest around midnight. Probably ayRhp1 mediates a symbiosomal NH4+-trapping mechanism that promotes nitrogen delivery to algae during the day - necessary to sustain photosynthesis-and restrict nitrogen delivery at night-to keep the algae under nitrogen limitation (Thies et al. 2022). | Eukaryota |
Metazoa, Cnidaria | Rhp1 of Acropora yongei |