This entry represents the conserved C-terminal region of BLTP1 protein (also known as Tweek/KIAA1109) which was firstly described as the fragile site-associated protein FSA [1] and has been associated with susceptibility to coeliac disease [2] polycystic kidney disease [3]. BLTP1 is a tube-forming lipid transport protein which provides phosphatidylethanolamine for glycosylphosphatidylinositol (GPI) anchor synthesis in the ER. It plays a role in endosomal trafficking and endosome recycling and it is also involved in the actin cytoskeleton and cilia structural dynamics [4,5]. BLTP1 also acts as a regulator of phagocytosis [6]. It belong to the RBG (repetitive beta-groove) superfamily. It has the conserved structure consisting of multiple repeating modules formed by five beta-sheets followed by a loop.

1: Molecular cloning of Chinese hamster 1q31 chromosomal fragile site DNA that is important to mdr1 gene amplification reveals a novel gene whose expression is associated with spermatocyte and adipocyte differentiation. Wei Y, Lin-Lee YC, Yang X, Dai W, Zhao S, Rassool FV, Elgart GW, Feun L, Savaraj N, Kuo MT; Gene. 2006;372:44-52. PMID:16545529

2: A genome-wide association study for celiac disease identifies risk variants in the region harboring IL2 and IL21. van Heel DA, Franke L, Hunt KA, Gwilliam R, Zhernakova A, Inouye M, Wapenaar MC, Barnardo MC, Bethel G, Holmes GK, Feighery C, Jewell D, Kelleher D, Kumar P, Travis S, Walters JR, Sanders DS, Howdle P, Swift J, Playford RJ, McLaren WM, Mearin ML, Mulder C Nat Genet. 2007;39:827-829. PMID:17558408

3: G8: a novel domain associated with polycystic kidney disease and non-syndromic hearing loss. He QY, Liu XH, Li Q, Studholme DJ, Li XW, Liang SP; Bioinformatics. 2006;22:2189-2191. PMID:16632497

4: Endosomal trafficking defects in patient cells with KIAA1109 biallelic variants. Kane MS, Diamonstein CJ, Hauser N, Deeken JF, Niederhuber JE, Vilboux T; Genes Dis. 2019;6:56-67. PMID:30906834

5: A novel superfamily of bridge-like lipid transfer proteins. Neuman SD, Levine TP, Bashirullah A; Trends Cell Biol. 2022;32:962-974. PMID:35491307

6: Systematic Identification of Host Cell Regulators of Legionella pneumophila Pathogenesis Using a Genome-wide CRISPR Screen. Jeng EE, Bhadkamkar V, Ibe NU, Gause H, Jiang L, Chan J, Jian R, Jimenez-Morales D, Stevenson E, Krogan NJ, Swaney DL, Snyder MP, Mukherjee S, Bassik MC; Cell Host Microbe. 2019;26:551-563. PMID:31540829

7: Vps13-like proteins provide phosphatidylethanolamine for GPI anchor synthesis in the ER. Toulmay A, Whittle FB, Yang J, Bai X, Diarra J, Banerjee S, Levine TP, Golden A, Prinz WA; J Cell Biol. 2022; [Epub ahead of print] PMID:35015055