Domain of unknown function

[1] The DUF designation is tentative, and such families tend to be renamed to a more specific name (or merged to an existing domain) after a function is identified.

[2][3] The DUF naming scheme was introduced by Chris Ponting, through the addition of DUF1 and DUF2 to the SMART database.

[5] Some DUF families share remote sequence homology with domains that has characterized function.

A total of 2,786 bacterial Pfam domains even occur in animals, including 320 DUFs.

[8] While this function is not essential, it helps the cells to adapt to low nutrient conditions by shutting down protein biosynthesis.

[8] It is thus believed that many DUFs (or proteins of unknown function, PUFs) are only required under certain conditions.