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Key Documents

ABC1442

Sigma-Aldrich

Anti-K-Ras4A Antibody, Isoform-specific

from rabbit, purified by affinity chromatography

Synonym(s):

GTPase KRas, isoform 2A, c-K-ras, isoform 2A, K-Ras4A, c-Ki-ras, isoform 2A, K-Ras 2, isoform 2A, Ki-Ras, isoform 2A

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About This Item

UNSPSC Code:
12352203
eCl@ss:
32160702
NACRES:
NA.43

biological source

rabbit

Quality Level

antibody form

affinity isolated antibody

antibody product type

primary antibodies

clone

polyclonal

purified by

affinity chromatography

species reactivity

human

technique(s)

western blot: suitable

NCBI accession no.

UniProt accession no.

shipped in

ambient

target post-translational modification

unmodified

Gene Information

human ... KRAS(3845)

General description

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.

Specificity

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).

Immunogen

KLH-conjugated linear peptide corresponding to a sequence near the C-terminus of human K-Ras4A.

Application

Detect K-Ras4A using this rabbit polyclonal Anti-K-Ras4A Antibody, Cat. No. ABC1442, validated for use in Western Blotting.
Research Category
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).

Quality

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.

Target description

21.66 kDa (pro-form, a.a. 1-189) and 21.17 kDa (mature, a.a. 2-186) calculated.

Physical form

Affinity purified.
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.

Other Notes

Concentration: Please refer to lot specific datasheet.

Disclaimer

Unless otherwise stated in our catalog or other company documentation accompanying the product(s), our products are intended for research use only and are not to be used for any other purpose, which includes but is not limited to, unauthorized commercial uses, in vitro diagnostic uses, ex vivo or in vivo therapeutic uses or any type of consumption or application to humans or animals.

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Storage Class Code

12 - Non Combustible Liquids

WGK

WGK 1

Flash Point(F)

Not applicable

Flash Point(C)

Not applicable


Certificates of Analysis (COA)

Search for Certificates of Analysis (COA) by entering the products Lot/Batch Number. Lot and Batch Numbers can be found on a product’s label following the words ‘Lot’ or ‘Batch’.

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Validation of antibody specificity is essential for the accurate evaluation of protein expression. For antibodies that recognize the gene products of the RAS family of oncogenes (HRAS, KRAS, and NRAS), an important challenge is the determination of selectivity for the
Marina Salmón et al.
Proceedings of the National Academy of Sciences of the United States of America, 118(30) (2021-07-25)
In mammals, the KRAS locus encodes two protein isoforms, KRAS4A and KRAS4B, which differ only in their C terminus via alternative splicing of distinct fourth exons. Previous studies have shown that whereas KRAS expression is essential for mouse development, the
Sara Canovas Nunes et al.
Blood cancer journal, 12(4), 64-64 (2022-04-16)
RAS mutations prevalent in high-risk leukemia have been linked to relapse and chemotherapy resistance. Efforts to directly target RAS proteins have been largely unsuccessful. However, since RAS-mediated transformation is dependent on signaling through the RAS-related C3 botulinum toxin substrate (RAC)

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