TCDB is operated by the Saier Lab Bioinformatics Group
TCIDNameDomainKingdom/PhylumProtein(s)
*1.A.23.1.1









Minor K+-dependent MscS-type mechanosensitive channel protein, designated KefA, AefA or MscK, (Edwards et al. 2012).

Bacteria
Proteobacteria
KefA (AefA) of E. coli
*1.A.23.1.2









The putative osmoadaptation receptor, BspA
Bacteria
Proteobacteria
BspA of Erwinia (Pectobacterium) chrysanthemi
*1.A.23.1.3









Mini conductance (300 pS) mechanosensitive channel, YjeP or MscM (1107aas; 13 TMSs in a 1 + 12 TMS arrangement).  Encoded in an operon with phosphatidyl serine decarboxylase (Moraes and Reithmeier 2012). Protects against hypoosmotic shock (Edwards et al. 2012).

Bacteria
Proteobacteria
YjeP of E. coli (P39285)
*1.A.23.1.4









Uncharacterized protein of 571 aas and 6 TMSs.

Bacteria
Proteobacteria
UP of Bdellovibrio exovorus
*1.A.23.2.1









Major MscS channel protein, YggB. Seven residues, mostly hydrophobic, in the first and second transmembrane helices are lipid-sensing residues (Malcolm et al., 2011).  X-ray structures are available (Lai et al. 2013).  The cytoplasmic cage domain senses macromolecular crowding (Rowe et al. 2014). A gating mechanism has been proposed (Malcolm et al. 2015).  The thermodynamics of K+ leak have been studied (Koprowski et al. 2015).  In the MscS crystal structure (PDB 2OAU ), a narrow, hydrophobic opening is visible in the crystal structure, and a vapor lock, created by hydrophobic seals consisting of L105 and L109, is the barrier to water and ions (Rasmussen et al. 2015). The voltage dependence of inactivation occurs independently of the positive charges of R46, R54, and R74 (Nomura et al. 2016).

Bacteria
Proteobacteria
YggB of E. coli (P0C0S1)
*1.A.23.2.2









MscS protein.  The x-ray structure at 4.2 Å is available (Lai et al. 2013).

Bacteria
Proteobacteria
MscS of Helicobacter pylori
*1.A.23.2.3









MscS mechanosensitive channel of 462 aas and 5 TMSs.

Bacteria
Candidatus Peregrinibacteria
MscS channel of Candidatus Peribacter riflensis
*1.A.23.3.1









The YkuT osmolyte efflux channel
Bacteria
Firmicutes
YkuT of Bacillus subtilis
*1.A.23.3.2









Mechanosensitive NaCl-inducible RpoS-dependent channel (1,000 pS), YbiO (741 aas; 10TMSs).  Protects agains hypoosmotic shock (Edwards et al. 2012).

Bacteria
Proteobacteria
YbiO of E. coli (P75783)
*1.A.23.3.3









Mechanosensitive channel, small conductance, YggB or MscCG (533 aas; 6-7 TMSs).  Mediates glutamate efflux (Becker et al. 2013).  The pore domain is in the N-terminus.  The C-terminus includes three subdomains, the periplasmic loop, the fourth transmembrane segment, and the cytoplasmic loop, all of which are important for MscCG function, in particular for glutamate excretion (Becker and Krämer 2015).

 

Bacteria
Actinobacteria
YggB or MscCG of Corynebacterium glutamicum (P42531)
*1.A.23.4.1









The MscMJ mechanosensitive channel
Archaea
Euryarchaeota
MscMJ of Methanococcus jannaschii
*1.A.23.4.2









The MscMJLR mechanosensitive channel
Archaea
Euryarchaeota
MscMJLR of Methanococcus jannaschii
*1.A.23.4.3









Mechanosensative channel with a conductance of 100 pS, YnaI (344aas; 4TMSs).  Protects against hypoosmotic shock (Edwards et al. 2012).  The structure has been solved by cryo-electron microscopy to a resolution of 13 A (Böttcher et al. 2015). While the cytosolic vestibule is structurally similar to that in MscS, additional density is seen in the transmembrane region, consistent with the presence of two additional TMSs predicted for YnaI. The location of this density suggests that the extra TMSs are tilted, which could induce local membrane curvature extending the tension-sensing paddles seen in MscS. Off-center lipid-accessible cavities are seen that resemble gaps between the sensor paddles in MscS. The conservation of the tapered shape and the cavities in YnaI suggest a mechanism similar to that of MscS (Böttcher et al. 2015). The voltage dependence of inactivation occurs independently of the positive charges of R46, R54, and R74 (Nomura et al. 2016).

Bacteria
Proteobacteria
YnaI of E. coli (P0AEB5)
*1.A.23.4.4









Plant plastid mechanosensitive channel MscS-like-2 (Msl2) (controls plastid organellar morphology, as does Msl3) (Haswell and Meyerowitz, 2006Haswell et al., 2008). It functions as do the bacterial homologues, but is essential for leaf growth, chloroplast integrity and normal starch accumulation (Jensen and Haswell 2012).  msl2 msl3 double mutant seedlings exhibit several hallmarks of drought or environmental osmotic stress, including solute accumulation, elevated levels of the compatible osmolyte proline (Pro), and accumulation of the stress hormone abscisic acid (ABA). Furthermore, msl2 msl3 mutants expressed Pro and ABA metabolism genes in a pattern normally seen under drought or osmotic stress. Pro accumulation in the msl2 msl3 mutant was suppressed by conditions that reduce plastid osmotic stress leading to the conclusion that these channels function like their bacterial homologues (Wilson et al. 2014).

Eukaryota
Viridiplantae
Msl2 of Arabidopsis thaliana (Q56X46)
*1.A.23.4.5









MscM (YbdG) is a distant member of the MscS family. It displays miniconductance (MscM) activity (Schumann et al., 2010; Edwards et al. 2012).

Bacteria
Proteobacteria
MscM (YbdG) of E. coli (P0AAT4)
*1.A.23.4.6









Mechanosensitive channel, MscS

Archaea
Crenarchaeota
MscS of Sulfolobus islandicus (C4KE93)
*1.A.23.4.7









Mechanosensitive ion channel protein 8 (Mechanosensitive channel of small conductance-like 8) (MscS-Like protein 8) is a pollen-specific, membrane tension-gated ion channel required for pollen to survive the hypoosmotic shock of rehydration and for full male fertility. It negatively regulates pollen germination but is required for cellular integrity during germination and tube growth. MSL8 thus senses and responds to changes in membrane tension associated with pollen hydration and germination (Hamilton et al. 2015).

Eukaryota
Viridiplantae
MSL8 of Arabidopsis thaliana
*1.A.23.4.8









Mechanosensitive ion channel protein 5 (Mechanosensitive channel of small conductance-like 5) (MscS-Like protein 5)
Eukaryota
Viridiplantae
MSL5 of Arabidopsis thaliana
*1.A.23.4.9









Putative small conductance mechanosensitive channel; Calcium channel, MacS

Eukaryota
Fungi
MacS of Mycosphaerella graminicola (Zymoseptoria tritici)
*1.A.23.4.10









Uncharacterized MscS homologue

Bacteria
Proteobacteria
MscS homologue of Helicobacter pylori
*1.A.23.4.11









MscS-like channel, MSL1. Mechanosensitive ion channel protein 1, mitochondrial.

Eukaryota
Viridiplantae
MSL1 of Arabidopsis thaliana
*1.A.23.4.12









Uncharacterized MscS channel of 351 aas and 4 N-terminal TMSs.

Bacteria
Proteobacteria
UP of Bdellovibrio bacteriovorus
*1.A.23.5.1









The cyclic nucleotide-binding MscS homologue, MT2508 (the C-terminal domain is the CAP_ED domain CD00038). It lacks mechanosensitivity but is ligand-gated by cyclic nucleotides (Caldwell et al., 2010).

Bacteria
Actinobacteria
MscS homologue, MT2508 of Mycobacterium tuberculosis (P71915)
*1.A.23.6.1









Chloroplast mechanosensitive channel, Msc1 (anions are preferred over cations) (Nakayama et al., 2007).
Eukaryota
Viridiplantae
Msc1 of Chlamydomonas reinhardtii (A3KE12)
*1.A.23.7.1









MscS homologue

Bacteria
Actinobacteria
MscS homologue of Streptomyces coelicolor
*1.A.23.7.2









MscS homologue

Bacteria
Proteobacteria
MscS of Myxococcus xanthus