TCDB is operated by the Saier Lab Bioinformatics Group

 9.B.36 The Acid Resistance Membrane Protein (HdeD) Family

The HdeD protein of E. coli is a 190 aa protein required for induction of acid resistance in response to overexpression of the AraC-type regulator, YdeO (Masuda and Church, 2003). It has 6 TMSs in a 2 + 2 + 2 arrangement. Evidence for an internally triplicated 2 TMS element was found. This protein may function with a 194 aa, 2 TMS protein (gi #3288672).

Homologues of HdeD include the DR3 protein of the moss, Tortula rutalis (223 aas; AAN87348) which also has 6 putative TMSs. Other homologues are annotated 'putative permease.' Homologues are generally of 160-240 aas in length with 6 TMSs in a 2 + 2 + 2 or 3 + 3 TMS arrangement, where the latter proteins show the first 3 TMSs are separated by larger hydrophilic loops than the last 3 TMSs. They derive from proteobacteria, cyanobacteria, plants, low and high G C Gram-positive bacteria and archaea. Some are much bigger (>450 aas) due to the presence of large hydrophilic extensions.  This is a large superfamily with over 10 families (see entries under 9.B.36).  These proteins are known as the DUF4386 domain proteins.

References associated with 9.B.36 family:

Benton, R., K.S. Vannice, and L.B. Vosshall. (2007). An essential role for a CD36-related receptor in pheromone detection in Drosophila. Nature 450: 289-293. 17943085
Gomez-Diaz, C., B. Bargeton, L. Abuin, N. Bukar, J.H. Reina, T. Bartoi, M. Graf, H. Ong, M.H. Ulbrich, J.F. Masson, and R. Benton. (2016). A CD36 ectodomain mediates insect pheromone detection via a putative tunnelling mechanism. Nat Commun 7: 11866. 27302750
Jin, X., T.S. Ha, and D.P. Smith. (2008). SNMP is a signaling component required for pheromone sensitivity in Drosophila. Proc. Natl. Acad. Sci. USA 105: 10996-11001. 18653762
Krin, E., A. Danchin, and O. Soutourina. (2010). Decrypting the H-NS-dependent regulatory cascade of acid stress resistance in Escherichia coli. BMC Microbiol 10: 273. 21034467
Lalaouna, D., K. Prévost, G. Laliberté, V. Houé, and E. Massé. (2018). Contrasting silencing mechanisms of the same target mRNA by two regulatory RNAs in Escherichia coli. Nucleic Acids Res 46: 2600-2612. 29294085
Masuda, N. and G.M. Church. (2003). Regulatory network of acid resistance genes in Escherichia coli. Mol. Microbiol. 48: 699-712. 12694615
Mates, A.K., A.K. Sayed, and J.W. Foster. (2007). Products of the Escherichia coli acid fitness island attenuate metabolite stress at extremely low pH and mediate a cell density-dependent acid resistance. J. Bacteriol. 189: 2759-2768. 17259322
Xu, S., A. Jay, K. Brunaldi, N. Huang, and J.A. Hamilton. (2013). CD36 Enhances Fatty Acid Uptake by Increasing the Rate of Intracellular Esterification but Not Transport across the Plasma Membrane. Biochemistry 52: 7254-7261. 24090054
Zhang, L., Y. Zhang, L. Zhang, X. Yang, and Z. Lv. (2009). Lupeol, a dietary triterpene, inhibited growth, and induced apoptosis through down-regulation of DR3 in SMMC7721 cells. Cancer Invest 27: 163-170. 19235588