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Updated: May 18, 2026
Fully Processed Recombinant KRAS4b: Isolating and Characterizing the Farnesylated and Methylated Protein
Published on: January 16, 2020
High yield production of C-terminally processed KRAS4a, HRAS, and NRAS for biophysical study
Shelley Perkins1, Sophie Krahnke1, Erik K Larsen1
1National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD, 21702, USA.
Abstract:
The classical RAS family of proteins consist of four isoforms HRAS, KRAS4a, KRAS4b, and NRAS, mutations in which lead to several types of human cancer, including pancreatic, colorectal, lung, and melanoma. RAS proteins function as molecular switches in the cell that control cell growth and proliferation. Two critical elements for RAS activation are loading of a molecule of GTP and localization to the plasma membrane. This last element is facilitated by the post-translational modification of the C-terminus, where three C-terminal residues are cleaved, and a cysteine is both farnesylated and methylated to generate a hydrophobic lipid tail that can insert into the membrane. Using an insect cell expression platform previously used to produce post-translationally modified KRAS4b, we describe a protocol here that leads to milligram quantities of protein for HRAS, KRAS4a, and NRAS targets. We also show that these proteins can bind the RAS binding domain of RAF1 and bind lipid nanodiscs. Production of these three post-translationally modified proteins is important for future novel drug-screening campaigns.
Insights
Researchers developed a new method to produce key RAS proteins (HRAS, KRAS4a, NRAS) crucial for cancer research. These modified proteins are essential for developing new cancer drugs and understanding cell growth regulation.
Area of Science:
- Molecular Biology
- Biochemistry
- Oncology
Background:
- The RAS protein family, including HRAS, KRAS4a, KRAS4b, and NRAS, is implicated in various human cancers.
- RAS proteins act as molecular switches regulating cell growth and proliferation.
- RAS activation requires GTP binding and plasma membrane localization, facilitated by C-terminal post-translational modifications.
Purpose of the Study:
- To establish a protocol for producing milligram quantities of post-translationally modified HRAS, KRAS4a, and NRAS.
- To enable future drug-screening campaigns targeting RAS proteins.
Main Methods:
- Utilized an insect cell expression platform.
- Adapted a previously established protocol for KRAS4b production.
- Characterized the produced proteins for their ability to bind RAF1 and lipid nanodiscs.
Main Results:
- Successfully produced milligram quantities of post-translationally modified HRAS, KRAS4a, and NRAS.
- Demonstrated that the produced proteins can bind the RAS binding domain of RAF1.
- Confirmed the ability of the proteins to bind lipid nanodiscs, indicating proper membrane localization.
Conclusions:
- The developed protocol yields sufficient quantities of modified RAS proteins for further research.
- These proteins are suitable for use in drug discovery and screening for novel cancer therapeutics.
- This work provides essential tools for advancing the study of RAS-driven cancers.
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