EEF2K (eukaryotic elongation factor 2 kinase)

Eukaryotic elongation factor 2 kinase (eEF-2K) (also known as Calmodulin (CaM)-dependent elongation factor 2 kinase,CaMKIII) is an unusual calcium/calmodulin (Ca/CaM)-dependent Threonin kinase that controls the rate of the elongation phase of protein synthesis through phosphorylating elongation factor 2 (eEF2) (Nairn et al., 1985; Ryazanov 1987; Mitsui et al., 1993; Redpath et al., 1993). Phosphorylation of eEF2 on Thr-56 disrupts the interaction between eEF-2 and the ribosome, leading to reduced protein synthesis. eEF-2K is regulated by phosphorylation by multiple signaling pathways and kinases at 11 different phosphorylation sides (Ryazanov et al., 1988; Carlberg et al., 1990; Abramczyk et al., 2011; Browne et al., 2004; Marshall et al., 2012; Chafouleas et al., 1981; Bowden et al., 2013). Hypoxia, nutrient deprivation and metabolic stress are all known to stimulate eEF-2K through activation of AMPK (Chafouleas et al., 1981).The activity of eEF-2K is increased in rapidly proliferating malignant cells and in cancer specimens, but is absent in normal adjacent tissues (Ashour et al., 2014b). eEF-2K promotes cell proliferation, invasion and tumorigenesis of some cancers. eEF-2K expression (mRNA) correlates with poor patient survival and prognosis (outcome) in some solid tumors, including breast , pancreatic cancer and glioblastoma (Meric-Bernstam et al., 2012). The activity of this kinase is increased in many cancers and may be a potential therapeutic target in some cancers.