| Casein kinase II regulatory subunit | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 structure of ck2 beta subunit crystallized in the presence of a p21waf1 peptide | |||||||||
| Identifiers | |||||||||
| Symbol | CK_II_beta | ||||||||
| Pfam | PF01214 | ||||||||
| InterPro | IPR000704 | ||||||||
| PROSITE | PDOC00845 | ||||||||
| SCOP2 | 1qf8 / SCOPe / SUPFAM | ||||||||
| |||||||||
Casein kinase II subunit beta is a protein that in humans is encoded by the CSNK2B gene. [5] [6] It is a ubiquitous protein kinase which regulates metabolic pathways, signal transduction, transcription, translation, and replication. The enzyme localizes to the endoplasmic reticulum and the Golgi apparatus. [7]
Casein kinase, a ubiquitous, well-conserved protein kinase involved in cell metabolism and differentiation, is characterised by its preference for Serine or Threonine in acidic stretches of amino acids. The enzyme is a tetramer of 2 alpha- and 2 beta-subunits. [8] [9] However, some species (e.g., mammals) possess 2 related forms of the alpha-subunit (alpha and alpha'), while others (e.g., fungi) possess 2 related beta-subunits (beta and beta'). [10] The alpha-subunit is the catalytic unit and contains regions characteristic of serine/threonine protein kinases. The beta-subunit is believed to be regulatory, possessing an N-terminal auto-phosphorylation site, an internal acidic domain, and a potential metal-binding motif. [10] The beta subunit is a highly conserved protein of about 25kDa that contains, in its central section, a cysteine-rich motif, CX(n)C, that could be involved in binding a metal such as zinc. [11] The mammalian beta-subunit gene promoter shares common features with those of other mammalian protein kinases and is closely related to the promoter of the regulatory subunit of cAMP-dependent protein kinase. [10]
