Transmembrane protein 18 also known as TMEM18 is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
which in humans is encoded by the ''TMEM18''
gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
.
Function
TMEM18 seems to affect energy levels through insulin and glucagon signaling, and in flies, its downregulation induces a metabolic state resembling type-II diabetes
Overexpression of the TMEM18 protein increases the
migration
Migration, migratory, or migrate may refer to: Human migration
* Human migration, physical movement by humans from one region to another
** International migration, when peoples cross state boundaries and stay in the host state for some minimum le ...
capacity of
neural stem cell
Neural stem cells (NSCs) are self-renewing, multipotent cells that firstly generate the radial glial progenitor cells that generate the neurons and glia of the nervous system of all animals during embryonic development. Some neural progenitor ste ...
s while inactivation of TMEM18 results in almost complete loss of migration activity.
The TMEM18 gene is ubiquitously expressed in both mammalian and fly tissues,
which suggests a basic cellular function. In the
mouse brain
The mouse brain refers to the brain of Mus musculus. Various brain atlases exist.
For reasons of reproducibility, genetically characterized, stable strains like C57BL/6 were chosen to produce high-resolution images and databases. Well known onli ...
, it is found in the majority of all cells, but is more abundant in neurons than other cell types.
Clinical significance
Genetic variants in the proximity of the TMEM18 gene are associated with
obesity
Obesity is a medical condition, sometimes considered a disease, in which excess body fat has accumulated to such an extent that it may negatively affect health. People are classified as obese when their body mass index (BMI)—a person's we ...
,
insulin levels, and blood sugar levels
Evolutionary history
The TMEM18 gene has a long evolutionary history as it is present in both plants and animals.
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. 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.
References
Further reading
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