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Aliases TMEM18, transmembrane protein 18
External IDs HomoloGene: 138333 GeneCards: TMEM18
Species Human Mouse
RefSeq (mRNA)



RefSeq (protein)



Location (UCSC) Chr 2: 0.67 – 0.68 Mb n/a
PubMed search [1] n/a
View/Edit Human

Transmembrane protein 18 also known as TMEM18 is a protein which in humans is encoded by the TMEM18 gene.[2]


TMEM18 seems to affect energy levels through insulin and glucagon signaling, and in flies, its downregulation induces a metabolic state resembling type-II diabetes[3]

Overexpression of the TMEM18 protein increases the migration capacity of neural stem cells while inactivation of TMEM18 results in almost complete loss of migration activity.[4]

The TMEM18 gene is ubiquitously expressed in both mammalian and fly tissues,[3] which suggests a basic cellular function. In the mouse brain, it is found in the majority of all cells, but is more abundant in neurons than other cell types.[5]

Clinical significance[edit]

Genetic variants in the proximity of the TMEM18 gene are associated with obesity,[5][6][7][8][9] insulin levels, and blood sugar levels [3]

Evolutionary history[edit]

The TMEM18 gene has a long evolutionary history as it is present in both plants and animals.[3][5] The TMEM18 protein's amino acid sequence is well conserved, which suggests that it has retained its function since the divergence of human and plants. Interestingly, the gene seems to have been lost in two separate lineages, but is not found duplicated in any analyzed genomes. Hence, it is not essential for eukaryotic organisms, but there appears to be selection against multiple copies of the TMEM18 gene.[3]


  1. ^ "Human PubMed Reference:". 
  2. ^ Strausberg RL, Feingold EA, Grouse LH, et al. (December 2002). "Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences". Proc. Natl. Acad. Sci. U.S.A. 99 (26): 16899–903. doi:10.1073/pnas.242603899. PMC 139241Freely accessible. PMID 12477932. 
  3. ^ a b c d e Wiemerslage L, Gohel PA, Maestri G, Hilmarsson TG, Mickael M, Fredriksson R, Williams MJ, Schioth HB (2016). "The Drosophila ortholog of TMEM18 regulates insulin and glucagon-like signaling.". J Endocrinol. 229: 233–43. doi:10.1530/JOE-16-0040. PMID 27029472. 
  4. ^ Jurvansuu J, Zhao Y, Leung DS, Boulaire J, Yu YH, Ahmed S, Wang S (June 2008). "Transmembrane protein 18 enhances the tropism of neural stem cells for glioma cells". Cancer Res. 68 (12): 4614–22. doi:10.1158/0008-5472.CAN-07-5291. PMID 18559506. 
  5. ^ a b c Almén MS, Jacobsson JA, Shaik JH, Olszewski PK, Cedernaes J, Alsiö J, Sreedharan S, Levine AS, Fredriksson R, Marcus C, Schiöth HB (April 2010). "The obesity gene, TMEM18, is of ancient origin, found in majority of neuronal cells in all major brain regions and associated with obesity in severely obese children". BMC Med. Genet. 11: 58. doi:10.1186/1471-2350-11-58. PMC 2858727Freely accessible. PMID 20380707. 
  6. ^ Thorleifsson G, Walters GB, Gudbjartsson DF, et al. (January 2009). "Genome-wide association yields new sequence variants at seven loci that associate with measures of obesity". Nat. Genet. 41 (1): 18–24. doi:10.1038/ng.274. PMID 19079260. 
  7. ^ Willer CJ, Speliotes EK, Loos RJ, et al. (January 2009). "Six new loci associated with body mass index highlight a neuronal influence on body weight regulation". Nat. Genet. 41 (1): 24–34. doi:10.1038/ng.287. PMC 2695662Freely accessible. PMID 19079261. 
  8. ^ Zhao J, Bradfield JP, Li M, et al. (May 2009). "The role of obesity-associated loci identified in genome wide association studies in the determination of pediatric BMI". Obesity (Silver Spring). 17 (12): 2254–7. doi:10.1038/oby.2009.159. PMC 2860782Freely accessible. PMID 19478790. 
  9. ^ Renström F, Payne F, Nordström A, Brito EC, Rolandsson O, Hallmans G, Barroso I, Nordström P, Franks PW (April 2009). "Replication and extension of genome-wide association study results for obesity in 4923 adults from northern Sweden". Hum. Mol. Genet. 18 (8): 1489–96. doi:10.1093/hmg/ddp041. PMC 2664142Freely accessible. PMID 19164386. 

Further reading[edit]