Thymidine Kinase (TK1) is a highly conserved phosphotransferase that is present in most living cells. Thymidine Kinase catalyzes the phosphorylation reaction: deoxythymidine + ATP = deoxythymidine 5'-phosphate + ADP; it is thus involved in the reaction chain to introduce deoxythymidine into the DNA. Thymidine kinase is required for the action of many antiviral drugs, such as azidothymidine (AZT), and is is also used to select hybridoma cell lines in the production of monoclonal antibodies. T

This gene encodes a DNA topoisomerase, an enzyme that controls and alters the topologic states of DNA during transcription. This enzyme catalyzes the transient breaking and rejoining of a single strand of DNA which allows the strands to pass through one another, thus altering the topology of DNA. This gene is localized to chromosome 20 and has pseudogenes which reside on chromosomes 1 and 22. [provided by RefSeq, Jul 2008]

MEK5 is a dual specificity protein kinase belonging to thr Ser/Thr protein kinase family, (MAP kinase kinase family). It is activated by phosphorylation on Ser/Thr by MAP kinase kinases and interacts specifically with ERK5, and not with another MAP kinase like P38. This kinase specifically interacts with and activates MAPK7/ERK5. This kinase itself can be phosphorylated and activated by MAP3K3/MEKK3, as well as by atypical protein kinase C isoforms (aPKCs). It is not phosphorylated by RAFA,

This gene encodes glycyl-tRNA synthetase, one of the aminoacyl-tRNA synthetases that charge tRNAs with their cognate amino acids. The encoded enzyme is an (alpha)2 dimer which belongs to the class II family of tRNA synthetases. It has been shown to be a target of autoantibodies in the human autoimmune diseases, polymyositis or dermatomyositis. [provided by RefSeq, Jul 2008]

CD40 ligand (CD40L) is a 33 kDa type II membrane glycoprotein expressed mainly on the cell surface of activated T lymphocytes, but also exists as a soluble form extracellularly. CD40L is the ligand for CD40, a member of the TNF superfamily, which is expressed on the cell surface of B cells, macrophages/monocytes, dendritic cells, vascular endothelial cells, and epithelial cells. CD40L plays an important role in B cell proliferation, antibody class switching, modulation of apoptosis in the germ