PathScan^® Multiplex Western Cocktail I: Phospho-p90RSK, Phospho-Akt, Phospho-p44/42 MAPK (Erk1/2) and Phospho-S6 Ribosomal Protein Detection Cocktail I #5301

Akt, also referred to as PKB or Rac, plays a critical role in controlling the balance between survival and apoptosis (1-3). This protein kinase is activated by insulin and various growth and survival factors, and functions in a wortmannin-sensitive pathway involving PI3 kinase (2,3). Akt is activated by phospholipid binding and activation loop phosphorylation at Thr308 by PDK1 (4) and also by phosphorylation within the carboxy-terminus at Ser473.
Both p44 and p42 MAP kinases (Erk1 and Erk2) play a critical role in the regulation of cell growth and differentiation (5-8). MAP kinases are activated by a wide variety of extracellular signals including growth and neurotrophic factors, cytokines, hormones and neurotransmitters. Activation of MAP kinases occurs through phosphorylation of threonine and tyrosine (202 and 204 of human MAP kinase [Erk1] or 183 and 185 of rat Erk2) at the sequence T*EY* by a single upstream MAP kinase kinase (MEK) (9,10). One of the downstream targets of p44/42 MAPK is p90RSK.
To effectively promote growth and cell division in a sustained manner, growth factors and mitogens must upregulate translation (11,12). Growth factors and mitogens induce the activation of p70 S6 kinase, which in turn phosphorylates the S6 ribosomal protein. Phosphorylation of S6 correlates with an increase in translation, particularly of mRNAs with an oligopyrimidine tract in their 5+ untranslated regions (12).