MAP kinase (MAPK) pathways including ERK1/2, p38 and JNK are activated upon environmental stimulus by growth factors or cellular stress, such as UV irradiation. This signaling serves to transmit external stimuli to the nucleus and activate numerous transcription factors. This results in changes in gene expression required for cellular growth, differentiation and survival. One downstream effector of these signaling pathways is Elk-1, a transcription factor that regulates immediate early gene (IEG) expression via the serum response element (SRE) DNA consensus site. Elk-1 belongs to the ternary complex factor (TCF) subfamily, part of Ets (E twenty-six) oncogene family of transcription factors which contain a highly conserved DNA-binding domain (DBD, the Ets domain) comprised of 85 amino acids. The TCF subfamily consists of three members ELK-1, SAP-1 and SAP-2/Net which are distinct gene products with different chromosomal localizations in both the mouse and human genomes. Each of the TCFs contains three conserved domains including the N-terminal Ets DNA binding domain, B-box region engaged in the interaction with serum response factor (SRF) to form ternary complex, and C-terminal transcriptional activation domain. Elk-1 can be activated by either pathway of ERK, JNK, or p38 through phosphorylation and de-SUMOylation. SUMO modification of Elk-1 by ERK pathway represses its transcriptional activity via SUMO dependent recruitment of histone deacetylases. Phosphorylated and de-sumoylated ELK-1 translocates to the nucleus from the cytoplasm and binds to SRE DNA sequences containing a central GGAA/T motif to initiate expressions of involved genes.

Upon receipt, the positive control should be removed and stored at -20^° or -80^°C. The remainder of the kit can be stored for up to 6 months at 2-8^°C from the date of shipment. Opened Microplate Wells or reagents may be stored for up to 1 month at 2^° to 8^°C. Return unused wells to the pouch containing desiccant pack, reseal along entire edge.
Note: The kit can be used within one year if the whole kit is stored at -20^°C upon receipt. Avoid repeated freeze-thaw cycles.