This domain can be found in bacterial, plant and other metazoa transmembrane proteins TMEM131L and TMEM131. Many of the members are multi-pass transmembrane proteins. This domain represents the N-terminal region [].Transmembrane protein 131-like (TMEM131L) was identified as a negative regulator of thymocyte proliferation that acts through mixed Wnt-dependent and independent mechanisms. It has two isoforms, L and S, which have different subcellular localisation. L isoform, the membrane-associated form, inhibits canonical Wnt/beta-catenin signalling through the induction of lysosome-dependent degradation of the active phosphorylated form of the LRP6 coreceptor. This protein was firstly described as containing three conserved homology domains (CHD1, 2 and 3), a transmembrane region and a C-terminal serine-rich region []. Using structure prediction models from AlphaFold, it has been possible to identify the CHDs as Ig-like domains.TMEM131 is a collagen binding transmembrane protein involved in collagen secretion by recruiting the ER-to-Golgi transport complex TRAPPIII []. Human TMEM131 is predicted to contain eight Ig-like domains.
