This family includes Transmembrane protein 106A/B/C, type II transmembrane proteins which have homology to the late embryogenesis abundant-2 (LEA-2) domain [5]. TMEM106A has been identified as a key factor to regulate macrophage activation and a tumour suppressor in gastric, renal cancer and non small-cell lung carcinoma (NSCLC) [1,2]. TMEM106B localises to late endosomes and lysosomes, and it is involved in dendrite morphogenesis and maintenance by regulating lysosomal trafficking via its interaction with MAP6 [3]. Its overexpression is associated with familial frontotemporal lobar degeneration [4]. It has also been identified as a protein required for productive SARS-CoV-2 [5]. Structural analysis of LEA-2 domains revealed that they have a long, conserved lipid-binding groove, implying that TMEM106B and its homologues Vac7 and Tag1 from yeast, may all be lipid transfer proteins in the lumen of late endocytic organelles [5].

1: TMEM106A inhibits cell proliferation, migration, and induces apoptosis of lung cancer cells. Liu J, Zhu H; J Cell Biochem. 2018; [Epub ahead of print] PMID:30456879

2: TMEM106a is a Novel Tumor Suppressor in Human Renal Cancer. Wu C, Xu J, Wang H, Zhang J, Zhong J, Zou X, Chen Y, Yang G, Zhong Y, Lai D, Li X, Tang A; Kidney Blood Press Res. 2017;42:853-864. PMID:29131025

3: The FTLD risk factor TMEM106B and MAP6 control dendritic trafficking of lysosomes. Schwenk BM, Lang CM, Hogl S, Tahirovic S, Orozco D, Rentzsch K, Lichtenthaler SF, Hoogenraad CC, Capell A, Haass C, Edbauer D; EMBO J. 2014;33:450-467. PMID:24357581

4: The frontotemporal lobar degeneration risk factor, TMEM106B, regulates lysosomal morphology and function. Brady OA, Zheng Y, Murphy K, Huang M, Hu F; Hum Mol Genet. 2013;22:685-695. PMID:23136129

5: TMEM106B in humans and Vac7 and Tag1 in yeast are predicted to be lipid transfer proteins. Levine TP; Proteins. 2022;90:164-175. PMID:34347309