8.A.121.1.1
TMEM237 (ALS2CR4) has 408 aas with 4 C-terminal TMSs.  It interacts with the human riboflavin transporter, (h)RFVT-3 (TC#2.A.125.1.2). TMEM237 co-localizes with hRFVT-3 and expressing it caused induces RF uptake, while its knockdown leads to a reduction in uptake. Transfecting TMEM237 into HuTu-80 cells also led to a marked enhancement in hRFVT-3 protein stability, and the level of expression of TMEM237 was reduced following treatment with TNF-alpha (a pro- inflammatory cytokine that inhibits intestinal RF uptake), while its expression was significantly upregulated following treatment with butyrate (an inducer of intestinal RF uptake). Thus, TMEM237 is an interactor with intestinal hRFVT-3, and this interaction affects its stability and activity (Sabui et al. 2019).