The TLC (TRAM-LAG1-CLN8) domain is an about 200-residue domain found in a
family of membrane-associated proteins related to yeast LAG1 and mammalian
TRAM. It is predicted to contain five transmembrane α helices [1].
Although the role of the TLC domain is not known, four possible function have
been suggested:
it could catalyze the synthesis of ceramide-like moieties and/or activate
lipid synthesis,
it could protect proteins from proteolyis,
it could be involved in lipid transport,
or it could also act as a lipid sensor.
Some proteins known to contain a TLC domain are listed below:
Vertebrate TRAM (translocation associated protein), a regulator of
polypeptide translocation into the ER and appears to modulate the exposure
of translocating proteins in the cytosol.
Yeast Longevity-assurance protein 1 (LAG1), a regulator of longevity and
ageing. It facilitates endoplasmic reticulum to Golgi transport of
glycosylphosphatidylinositol (GPI)-anchored proteins.
Mammalian CLN8, a multi-pass transmembrane protein, which is localized
mainly to the endoplasmic reticulum (ER) and partially to the ER-Golgi
intermediate compartment. In human, defects in CLN8 are a cause of
progressive epilepsy with mental retardation (EPMR); also known as neuronal
ceroid lipofuscinosis (NCL) type 8 and Northern epilepsy. In mouse, defects
in CLN8 are the cause of the phenotype motor neuron degeneration (mnd),
which is a naturally occuring NCL.
The profile we developed spans the entire TLC domain.
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