| HKDC1 | |||||||||||||||||||||||||||||||||||||||||||||||||||
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| Aliases | HKDC1 , hexokinase domain containing 1, RP92 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| External IDs | OMIM: 617221 MGI: 2384910 HomoloGene: 128937 GeneCards: HKDC1 | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Hexokinase domain containing 1 (HKDC1) is an enzyme which in humans is encoded by the HKDC1 gene on chromosome 10. [5] It is a recently discovered hexokinase isoform that likely phosphorylates glucose in maternal metabolism during pregnancy. [6] [7]
The HKDC1 gene is oriented in a head-to-tail arrangement next to the HK1 gene on chromosome 10. [7] [8] This arrangement, along with its amino acid sequence similarity to HK1, suggests that HKDC1 and HK1 derived from the same precursor via a tandem gene duplication event. [6] [7] [8] The similarity between HKDC1 and HK1 may have obscured its discovery in earlier screens for vertebrate hexokinases. [6] Unlike the HK2 pseudogene, HKDC1 contains an intact open reading frame of 917 residues and is conserved across animal species, indicating that it encodes a functional protein. Moreover, 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, indicating that its C-terminal is capable of hexokinase activity. [7] [8]
As the recently 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. [9] Though its particular biological function remains unclear, HKDC1 has been suggested to play a more major role in glucose metabolism during pregnancy, as the mother would need to provide enough energy for both herself and the fetus. [6] [7] HKDC1 is ubiquitously expressed, with the highest levels of expression in pharynx, thymus, colon, esophagus, and eye tissue. [7] [8]
Compared to the other hexokinases, HKDC1 was dramatically overexpressed in cancer tissues, indicating that this isoform might play an important and different role in cancer growth. Further experiments clarifying this role will be required for developing HKDC1 as a therapeutic target. [9]
Several regulatory variants, including various enhancers, targeting HKDC1 expression have been associated with gestational hyperglycemia in pregnant women. [6] Considering that maternal glucose levels during pregnancy impact both the fetal and later health outcomes, a greater understanding of the genetic mechanisms underlying maternal glycemia during pregnancy may help identify and aid such women at risk. [6] [7]
Phosphofructokinase-2 (6-phosphofructo-2-kinase, PFK-2) or fructose bisphosphatase-2 (FBPase-2), is an enzyme indirectly responsible for regulating the rates of glycolysis and gluconeogenesis in cells. It catalyzes formation and degradation of a significant allosteric regulator, fructose-2,6-bisphosphate (Fru-2,6-P2) from substrate fructose-6-phosphate. Fru-2,6-P2 contributes to the rate-determining step of glycolysis as it activates enzyme phosphofructokinase 1 in the glycolysis pathway, and inhibits fructose-1,6-bisphosphatase 1 in gluconeogenesis. Since Fru-2,6-P2 differentially regulates glycolysis and gluconeogenesis, it can act as a key signal to switch between the opposing pathways. Because PFK-2 produces Fru-2,6-P2 in response to hormonal signaling, metabolism can be more sensitively and efficiently controlled to align with the organism's glycolytic needs. This enzyme participates in fructose and mannose metabolism. The enzyme is important in the regulation of hepatic carbohydrate metabolism and is found in greatest quantities in the liver, kidney and heart. In mammals, several genes often encode different isoforms, each of which differs in its tissue distribution and enzymatic activity. The family described here bears a resemblance to the ATP-driven phospho-fructokinases, however, they share little sequence similarity, although a few residues seem key to their interaction with fructose 6-phosphate.
PDE3 is a phosphodiesterase. The PDEs belong to at least eleven related gene families, which are different in their primary structure, substrate affinity, responses to effectors, and regulation mechanism. Most of the PDE families are composed of more than one gene. PDE3 is clinically significant because of its role in regulating heart muscle, vascular smooth muscle and platelet aggregation. PDE3 inhibitors have been developed as pharmaceuticals, but their use is limited by arrhythmic effects and they can increase mortality in some applications.
Rev-Erb alpha (Rev-Erbɑ), also known as nuclear receptor subfamily 1 group D member 1 (NR1D1), is one of two Rev-Erb proteins in the nuclear receptor (NR) family of intracellular transcription factors. In humans, REV-ERBɑ is encoded by the NR1D1 gene, which is highly conserved across animal species.
HNF1 homeobox A, also known as HNF1A, is a human gene on chromosome 12. It is ubiquitously expressed in many tissues and cell types. The protein encoded by this gene is a transcription factor that is highly expressed in the liver and is involved in the regulation of the expression of several liver-specific genes. Mutations in the HNF1A gene have been known to cause diabetes. The HNF1A gene also contains a SNP associated with increased risk of coronary artery disease.
Hexokinase-1 (HK1) is an enzyme that in humans is encoded by the HK1 gene on chromosome 10. Hexokinases phosphorylate glucose to produce glucose-6-phosphate (G6P), the first step in most glucose metabolism pathways. This gene encodes a ubiquitous form of hexokinase which localizes to the outer membrane of mitochondria. Mutations in this gene have been associated with hemolytic anemia due to hexokinase deficiency. Alternative splicing of this gene results in five transcript variants which encode different isoforms, some of which are tissue-specific. Each isoform has a distinct N-terminus; the remainder of the protein is identical among all the isoforms. A sixth transcript variant has been described, but due to the presence of several stop codons, it is not thought to encode a protein. [provided by RefSeq, Apr 2009]
Upstream stimulatory factor 1 is a protein that in humans is encoded by the USF1 gene.
PNKD is the abbreviation for a human neurological movement disorder paroxysmal nonkinesiogenic dyskinesia. Like many other human genetics disorders, PNKD also refers to the disease, the disease gene and the encoded protein. (PNKD) is a protein that in humans is encoded by the PNKD gene. Alternative splicing results in the transcription of three isoforms. The mouse ortholog is called brain protein 17 (Brp17).
Triple functional domain protein is a protein that in humans is encoded by the TRIO gene.
Hexokinase 2 also known as HK2 is an enzyme which in humans is encoded by the HK2 gene on chromosome 2. Hexokinases phosphorylate glucose to produce glucose-6-phosphate (G6P), the first step in most glucose metabolism pathways. This gene encodes hexokinase 2, the predominant form found in skeletal muscle. It localizes to the outer membrane of mitochondria. Expression of this gene is insulin-responsive, and studies in rat suggest that it is involved in the increased rate of glycolysis seen in rapidly growing cancer cells. [provided by RefSeq, Apr 2009]
Hexokinase 3 also known as HK3 is an enzyme which in humans is encoded by the HK3 gene on chromosome 5. Hexokinases phosphorylate glucose to produce glucose-6-phosphate (G6P), the first step in most glucose metabolism pathways. This gene encodes hexokinase 3. Similar to hexokinases 1 and 2, this allosteric enzyme is inhibited by its product glucose-6-phosphate. [provided by RefSeq, Apr 2009]
Iroquois-class homeodomain protein IRX-1, also known as Iroquois homeobox protein 1, is a protein that in humans is encoded by the IRX1 gene. All members of the Iroquois (IRO) family of proteins share two highly conserved features, encoding both a homeodomain and a characteristic IRO sequence motif. Members of this family are known to play numerous roles in early embryo patterning. IRX1 has also been shown to act as a tumor suppressor gene in several forms of cancer.
Chromosome 20 open reading frame 111, or C20orf111, is the hypothetical protein that in humans is encoded by the C20orf111 gene. C20orf111 is also known as Perit1, HSPC207, and dJ1183I21.1. It was originally located using genomic sequencing of chromosome 20. The National Center for Biotechnology Information, or NCBI, shows that it is located at q13.11 on chromosome 20, however the genome browser at the University of California-Santa Cruz (UCSC) website shows that it is at location q13.12, and within a million base pairs of the adenosine deaminase locus. It was also found to have an increase in expression in cells undergoing hydrogen peroxide(H
2O
2)-induced apoptosis. After analyzing the amino acid content of C20orf111, it was found to be rich in serine residues.
The TP53-inducible glycolysis and apoptosis regulator (TIGAR) also known as fructose-2,6-bisphosphatase TIGAR is an enzyme that in humans is encoded by the C12orf5 gene.
SH3D21 is a nuclear protein that is encoded by the SH3D21 gene. In humans, this gene is located on chromosome 1 p34.3. The human mRNA transcript is 2527 base pairs and the final protein product is 756 amino acids. While the exact function of this protein remains unknown, due to the presence of three SH3 domains, it has been implicated in protein-protein interactions.
C12orf40, also known as Chromosome 12 Open Reading Frame 40, HEL-206, and Epididymis Luminal Protein 206 is a protein that in humans is encoded by the C12orf40 gene.
Chromosome 1 open reading frame 112, is a protein that in humans is encoded by the C1orf112 gene, and is located at position 1q24.2. C1orf112 encodes for seventeen variants of mRNA, fifteen of which are functional proteins. C1orf112 has a determined precursor molecular weight of 96.6 kDa and an isoelectric point of 5.62. C1orf112 has been experimentally determined to localize to the mitochondria, although it does not contain a mitochondrial targeting sequence.
Transmembrane protein 171 (TMEM171) is a protein that in humans is encoded by the TMEM171 gene.
Chromosome 1 open reading frame 198 (C1orf198) is a protein that in humans is encoded by the C1orf198 gene. This particular gene does not have any paralogs in Homo sapiens, but many orthologs have been found throughout the Eukarya domain. C1orf198 has high levels of expression in all tissues throughout the human body, but is most highly expressed in lung, brain, and spinal cord tissues. Its function is most likely involved in lung development and hypoxia-associated events in the mitochondria, which are major consumers of oxygen in cells and are severely affected by decreases in available cellular oxygen.
C6orf136 is a protein in humans encoded by the C6orf136 gene. The gene is conserved in mammals, mollusks, as well some porifera. While the function of the gene is currently unknown, C6orf136 has been shown to be hypermethylated in response to FOXM1 expression in Head Neck Squamous Cell Carcinoma (HNSCC) tissue cells. Additionally, elevated expression of C6orf136 has been associated with improved survival rates in patients with bladder cancer. C6orf136 has three known isoforms.
Family with sequence similarity 13 member B is a protein which in humans is encoded by the FAM13B gene, also known as C5ORF5. The FAM13B gene is found in vertebrates and jawed fish. FAM13B is expressed ubiquitously in human tissues and has been linked to maglinant myelomas susceptibility to atrial fibrillation, a cardiac arrhythmia.
