HKDC1
Description
The HKDC1 (hexokinase domain containing 1) is a protein-coding gene located on chromosome 10.
Hexokinase domain containing 1 (HKDC1) is an enzyme encoded by the HKDC1 gene on chromosome 10 in humans. It is a recently discovered hexokinase isoform that likely phosphorylates glucose in maternal metabolism during pregnancy.
The HKDC1 gene is situated next to the HK1 gene on chromosome 10 in a head-to-tail arrangement. This arrangement, along with its amino acid sequence similarity to HK1, suggests that HKDC1 and HK1 originated from the same precursor through a tandem gene duplication event. The resemblance between HKDC1 and HK1 may have obscured its discovery in earlier screens for vertebrate hexokinases. Unlike the HK2 pseudogene, HKDC1 possesses an intact open reading frame of 917 residues and is conserved across animal species, indicating that it encodes a functional protein. Furthermore, the encoded protein contains conserved glucose-binding sites in its N- and C-terminal domains, as well as an ATP-binding site in its C-terminal domain, suggesting that its C-terminal is capable of hexokinase activity.
As the newly identified fifth isoform of hexokinase, HKDC1 catalyzes the rate-limiting and first obligatory step of glucose metabolism, which is the ATP-dependent phosphorylation of glucose to G6P. While its specific biological function remains unclear, HKDC1 has been proposed to play a more significant role in glucose metabolism during pregnancy, as the mother needs to provide sufficient energy for both herself and the fetus. HKDC1 is ubiquitously expressed, with the highest levels of expression in pharynx, thymus, colon, esophagus, and eye tissue.
Compared to other hexokinases, HKDC1 is dramatically overexpressed in cancer tissues, suggesting that this isoform might play a crucial and distinct role in cancer growth.
HKDC1 is also known as RP92.
