This family represents the conserved region of transmembrane protein 175 which is an organelle-specific potassium channel responsible for potassium conductance in endosomes and lysosomes. It forms a potassium-permeable leak-like channel, which regulates luminal pH stability and is required for autophagosome-lysosome fusion. TMEM175 is the major lysosomal potassium conductance [1,2]. It is present in eukaryotes, where TMEM175 has two repeats of 6-transmembrane-spanning segments, and also in prokaryotes in which it has one copy [1-3].

1: TMEM175 Is an Organelle K(+) Channel Regulating Lysosomal Function. Cang C, Aranda K, Seo YJ, Gasnier B, Ren D; Cell. 2015;162:1101-1112. PMID:26317472

2: The lysosomal potassium channel TMEM175 adopts a novel tetrameric architecture. Lee C, Guo J, Zeng W, Kim S, She J, Cang C, Ren D, Jiang Y; Nature. 2017;547:472-475. PMID:28723891

3: Structural basis for ion selectivity in TMEM175 K(+) channels. Brunner JD, Jakob RP, Schulze T, Neldner Y, Moroni A, Thiel G, Maier T, Schenck S; Elife. 2020; [Epub ahead of print] PMID:32267231