8STN

Crystal structure of KRAS-G12D/G75A mutant, GDP-bound

Summary for 8STN

• Entry DOI: 10.2210/pdb8stn/pdb
• Descriptor: GTPase KRas, GUANOSINE-5'-DIPHOSPHATE, MAGNESIUM ION, ... (6 entities in total)
• Functional Keywords: kras, ras, nucleotide-binding protein, signaling protein, oncoprotein
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 2
• Total formula weight: 39830.65

Authors

Tran, T.H.,Dharmaiah, S.,Simanshu, D.K. (deposition date: 2023-05-10, release date: 2023-08-23, Last modification date: 2023-10-11)

Primary citation

Yang, M.H.,Tran, T.H.,Hunt, B.,Agnor, R.,Johnson, C.W.,Shui, B.,Waybright, T.J.,Nowak, J.A.,Stephen, A.G.,Simanshu, D.K.,Haigis, K.M.
Allosteric Regulation of Switch-II Domain Controls KRAS Oncogenicity.
Cancer Res., 83:3176-3183, 2023

PubMed Abstract: RAS proteins are GTPases that regulate a wide range of cellular processes. RAS activity is dependent on its nucleotide-binding status, which is modulated by guanine nucleotide exchange factors (GEF) and GTPase-activating proteins (GAP). KRAS can be acetylated at lysine 104 (K104), and an acetylation-mimetic mutation of K104 to glutamine (K104Q) attenuates the in vitro-transforming capacity of oncogenic KRAS by interrupting GEF-induced nucleotide exchange. To assess the effect of this mutation in vivo, we used CRISPR-Cas9 to generate mouse models carrying the K104Q point mutation in wild-type and conditional KrasLSL-G12D alleles. Homozygous animals for K104Q were viable, fertile, and arose at the expected Mendelian frequency, indicating that K104Q is not a complete loss-of-function mutation. Consistent with our previous findings from in vitro studies, however, the oncogenic activity of KRASG12D was significantly attenuated by mutation at K104. Biochemical and structural analysis indicated that the G12D and K104Q mutations cooperate to suppress GEF-mediated nucleotide exchange, explaining the preferential effect of K104Q on oncogenic KRAS. Furthermore, K104 functioned in an allosteric network with M72, R73, and G75 on the α2 helix of the switch-II region. Intriguingly, point mutation of glycine 75 to alanine (G75A) also showed a strong negative regulatory effect on KRASG12D. These data demonstrate that lysine at position 104 is critical for the full oncogenic activity of mutant KRAS and suggest that modulating the sites in its allosteric network may provide a unique therapeutic approach in cancers expressing mutant KRAS.

PubMed: 37556505
DOI: 10.1158/0008-5472.CAN-22-3210

Experimental method

X-RAY DIFFRACTION (2.03 Å)