Download MendeleyStructural and functional analyses of a germline KRAS T50I mutation provide insights into Raf activation.
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.(2023) JCI Insight 8
- PubMed: 37681415
- DOI: https://doi.org/10.1172/jci.insight.168445
- Primary Citation of Related Structures:
7T1F - 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.
Organizational Affiliation:
Department of Pediatrics, UCSF, San Francisco, California, USA.
