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FB2026_01
,
released March 12, 2026
In genome-wide association studies (GWAS), the region of the human TMEM18 gene has been associated with obesity-related phenotypes. Little is known about the function of the protein encoded by TMEM18. There is a single fly ortholog, Dmel\Tmem18; there are no reported classical mutations for this fly gene, but RNAi-targeting constructs have been generated.
The human TMEM18 gene has not been introduced into flies.
Using a GAL4 driver expressed in the insulin-producing cells (IPCs) in the adult brain and a UAS-RNAi construct targeting Dmel\Tmem18, effects of reduced expression of Tmem18 on fly insulin pathways were assessed. Multiple related phenotypes were observed: reduced resistance to starvation, increased levels of circulating and stored carbohydrates, and increased lipid levels; expression of Dmel\Akh, a glucose-regulatory peptide hormone functionally similar to human glucagon, was significantly reduced.
[updated Jan. 2017 by FlyBase; FBrf0222196]
TMEM18 is associated with obesity, BMI, or weight in multiple GWAS studies (see GWAS Catalog, below in 'External links').
TMEM18 encodes a protein characterized as a transmembrane protein and a DNA-binding transcription repressor. [Gene Cards, TMEM18; 2017.01.27]
The 140-amino acid protein of TMEM18 has 4 transmembrane domains and a C-terminal nuclear localization signal. Immunohistochemical analysis showed that TMEM18 was expressed in the cytoplasm of human neural precursor cells (NPCs) and that it was concentrated around the nucleus. TMEM18 also localized to nuclear structures. (Jurvansuu et al. 2008; pubmed:18559506) [from MIM:613220; 2017.01.27]
One to one (1 human to 1 Drosophila).
High-scoring ortholog of human TMEM18 (1 Drosophila to 1 human). Dmel\Tmem18 shares 45% identity and 60% similarity with human TMEM18.