7T1F

Crystal structure of GDP-bound T50I mutant of human KRAS4B

Summary for 7T1F

• Entry DOI: 10.2210/pdb7t1f/pdb
• Descriptor: Isoform 2B of GTPase KRas, GUANOSINE-5'-DIPHOSPHATE, MAGNESIUM ION, ... (4 entities in total)
• Functional Keywords: kras, ras, t50i, kras4b, k-ras, oncoprotein
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 3
• Total formula weight: 59449.42

Authors

Zhang, Y.,Zhang, C. (deposition date: 2021-12-01, release date: 2022-12-14, Last modification date: 2023-12-27)

Primary citation

Chen, P.Y.,Huang, B.J.,Harris, M.,Boone, C.,Wang, W.,Carias, H.,Mesiona, B.,Mavrici, D.,Kohler, A.C.,Bollag, G.,Zhang, C.,Zhang, Y.,Shannon, K.
Structural and functional analyses of a germline KRAS T50I mutation provide insights into Raf activation.
JCI Insight, 8:-, 2023

PubMed Abstract: A T50I substitution in the K-Ras interswitch domain causes Noonan syndrome and emerged as a third-site mutation that restored the in vivo transforming activity and constitutive MAPK pathway activation by an attenuated KrasG12D,E37G oncogene in a mouse leukemia model. Biochemical and crystallographic data suggested that K-RasT50I increases MAPK signal output through a non-GTPase mechanism, potentially by promoting asymmetric Ras:Ras interactions between T50 and E162. We generated a "switchable" system in which K-Ras mutant proteins expressed at physiologic levels supplant the fms like tyrosine kinase 3 (FLT3) dependency of MOLM-13 leukemia cells lacking endogenous KRAS and used this system to interrogate single or compound G12D, T50I, D154Q, and E162L mutations. These studies support a key role for the asymmetric lateral assembly of K-Ras in a plasma membrane-distal orientation that promotes the formation of active Ras:Raf complexes in a membrane-proximal conformation. Disease-causing mutations such as T50I are a valuable starting point for illuminating normal Ras function, elucidating mechanisms of disease, and identifying potential therapeutic opportunities for Rasopathy disorders and cancer.

PubMed: 37681415
DOI: 10.1172/jci.insight.168445

Experimental method

X-RAY DIFFRACTION (2.2 Å)