Mouse Anti-Erk1/2 (MAPK), SB46b

Erk1 and Erk2 are closely related mitogen activated protein (MAP) kinases which are activated by many growth factors, mitogens, and differentiation-promoting agents via a protein kinase cascade. Erk1 and Erk2 are ubiquitous and abundant although their relative abundance in specific tissues may vary. The two kinases are nearly 85% identical and have higher identity in the core regions involved in substrate binding. Erk1 and Erk2 are activated approximately 1000-fold by phosphorylation within a Thr-Glu-Tyr motif in the activation loop on both threonine and tyrosine residues by Mek1 and Mek2. Both sites must be phosphorylated for maximum activity. These kinases in turn phosphorylate a variety of different substrates. Erk1 and Erk2 are found in the cytoplasm and are translocated to the nucleus upon activation. They target membrane proteins, cytosolic proteins, such as downstream kinases, and cytoskeletal proteins and nuclear proteins, such as transcription factors. Many of these substrates are important regulatory proteins. Erk1 and Erk2 represent proximal kinases in the classical kinase pathway which links growth and differentiation signals at the cell surface (through tyrosine kinases) with transcription in the nucleus. The SB46b monoclonal antibody precipitates ~42 kDa and ~44 kDa bands, corresponding to Erk1 and Erk2, respectively.