GTPase KRas (UniProt P01116; also known as c-K-ras, c-Ki-ras, K-Ras 2, Ki-Ras) is encoded by the KRAS (also known as KRAS2, RASK2) gene (Gene ID 3845) in human. Ras proteins are small GTPases controlling cellular pathways that signal for growth, proliferation, and differentiation. Mammalian genomes harbor three Ras genes (HRAS, NRAS, and KRAS) that encode four GTPases, two of which (K-Ras4A and K-Ras4B) are transcribed from the KRAS gene via two alternative fourth exons. Ras proteins share nearly identical sequence homology in sequence encoded by exons 1-3 (a.a. 1-165), while diverge in their C-terminal 24-a.a. hypervariable region (HVR) encoded by exon 4. The first 165 amino acids form the catalytic G domain that mediates GDP/GTP binding and association with effectors, exchange factors, and GTPase-activating proteins (GAPs), while the C-terminal HVR is needed for Ras membrane localization, a process necessary for Ras function. In addition to the removal of initiator methionine (Met1), Ras proteins are posttranslationally modified by farnesylation of Cys186, followed by proteolytical cleavage their C-terminal end three amino acids (a.a. 187-189) and carboxyl methylation of the newly formed C-terminal prenylcysteine. H-Ras, N-Ras, and K-Ras4A are further palmitoylated on cysteine residue(s) near the C-terminus (Cys181/Cys184 in H-Ras, Cys181 in N- and K-Ras), while K-Ras4B lacks a palmitoylation site. Palmitoylation is required for targeting H- and N-Ras to the plasma membrane (PM), while K-Ras4A and K-Ras4B contain a series of lysines that constitute a polybasic region (PBR) capable of interacting with the inner leaflet of the PM through an electrostatic interaction.
This rabbit polyclonal antibody specifically detected recombinant K-Ras4A, but not K-Ras4B, H-Ras or N-Ras (Tsai, F.D., et al. (2015). Proc. Natl. Acad. Sci. U. S. A. 112(3):779-784) by targeting a C-terminal region sequence unique to spliced isoform K-Ras4A (isoform 2A) and not found in spliced isoform K-Ras4B (isoform 2B).
KLH-conjugated linear peptide corresponding to a sequence near the C-terminus of human K-Ras4A.
Detect K-Ras4A using this rabbit polyclonal Anti-K-Ras4A Antibody, Cat. No. ABC1442, validated for use in Western Blotting.
Apoptosis & Cancer
Western Blotting Analysis: A representative lot detected recombinant K-Ras4A, but not K-Ras4B, H-Ras or N-Ras (Tsai, F.D., et al. (2015). Proc. Natl. Acad. Sci. U. S. A. 112(3):779-784).
Western Blotting Analysis: A representative lot detected the presence of K-Ras4A in total Ras immunoprecipitates from colorectal carcinoma (HCT116, HT29, and CaCo-2) and T24 urothelial carcinoma cell lysates using a pan-Ras mAb (Cat. No. OP40), clone RAS 10 (Tsai, F.D., et al. (2015). Proc. Natl. Acad. Sci. U. S. A. 112(3):779-784).
Evaluated by Western Blotting in HEK293 cell lysate.
Western Blotting Analysis: A 1:5,000 dilution of this antibody detected exogenously expressed K-Ras4A GFP fusion protein in 20 µg of lysate from transfected HEK293 cells.
21.66 kDa (pro-form, a.a. 1-189) and 21.17 kDa (mature, a.a. 2-186) calculated.
Purified rabbit polyclonal antibody in buffer containing 0.1 M Tris-Glycine (pH 7.4), 150 mM NaCl with 0.05% sodium azide
Storage and Stability
Stable for 1 year at 2-8°C from date of receipt.
Concentration: Please refer to lot specific datasheet.
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