Product Uses Include
- Cdc42 GEF binding studies
- Inhibition of Cdc42 GEFs in vitro
- Inhibition of Cdc42 in vivo by microinjection
Material
The dominant negative form of the Cdc42 protein (G25K isoform) contains a threonine to asparagine substitution at residue 17. The common name for this mutant is Cdc42(T17N) (or N17Cdc42). The asparagine substitution abolishes the protein's affinity for GTP and reduces its affinity for GDP. Hence, the Cdc42(T17N) is always in either a nucletiode free state or in its inactive, GDP-bound, state. Because of this, it binds strongly to Cdc42 GEFs and it blocks wild type Cdc42 from being activated by these GEFs.
Dominant negative form of human Cdc42 protein has been expressed in a bacterial system, and is available as a GST-tagged fusion protein. The recombinant protein is 50 kDa consisting of the Cdc42 protein (22 kDa) and a 28 kDa GST tag. The tag is at the amino terminal of the protein. The protein is supplied as a lyophilized powder. When it is reconstituted in distilled water to 1 mg/ml, the protein is in the following buffer: 2 mM Tris pH 7.6, 0.5 mM MgCl2, 0.5% sucrose, 0.1% dextran. Protein concentration is determined by the Precision Red Advanced Protein Assay Reagent (Cat # ADV02).
Purity
Purity is determined by scanning densitometry of proteins on SDS-PAGE gels. Samples are >90% pure, the major contaminant running at 28 kDa is GST protein.
Biological Activity
Activity of Cdc42(T17N) was verified by the ability of the protein to inhibit GEF activation of wild type Cdc42 in an in vitro GEF assay (Cat # BK100).
