The transcription factor Elk-1 is a component of the ternary complex that binds the serum response element (SRE) and mediates gene activity in response to serum and growth factors (1-3). Elk-1 is phosphorylated by MAP kinase pathways at a cluster of S/T motifs at its carboxy terminus, phosphorylation at these sites, particularly Ser383, is critical for transcriptional activation by Elk-1. Elk-1 appears to be a direct target of activated MAP kinase: (a) biochemical studies indicate that Elk-1 is a good substrate for MAP kinase, (b) the kinetics of Elk-1 phosphorylation and activation correlate with MAP kinase activity, (c) interfering mutants of MAP kinase block Elk-1 activation in vivo. Other studies have shown that Elk-1 (Ser383) is also a target of the stress-activated kinase SAPK/JNK (4,5). Molecular Weight: 40kD nonphosphorylated, 50kD phosphorylated Nonphosphorylated Elk1 fusion protein: Bacterially expressed GST-Elk1 fusion protein serves as a negative control. Supplied in SDS Sample Buffer. Store at -20C. Phosphorylated Elk1 fusion protein: GST-Elk1 phosphorylated by the Erk2 enzyme serves as a positive control. Supplied in SDS Sample Buffer. Store at -20C. Directions for Use: As controls, we recommend using 15ul of phosphorylated and nonphosphorylated Elk1 control extracts. Boil sample prior to loading. 150ul wil be sufficient for 10 blots. Western Blots: For controls, we recommend using 15ul of phosphorylated and nonphosphorylated Elk1 control extracts. Boil sample prior to loading.
