Novel Calcium-Binding Ablating Mutations Induce Constitutive RET Activity and Drive Tumorigenesis

Junya Tabata, Takashi Nakaoku, Mitsugu Araki, Ryunosuke Yoshino, Shinji Kohsaka, Ayaka Otsuka, Masachika Ikegami, Ayako Ui, Shin-Ichiro Kanno, Keiko Miyoshi, Shigeyuki Matsumoto, Yukari Sagae (+6 others)
Distinguishing oncogenic mutations from variants of unknown significance (VUS) is critical for precision cancer medicine. Here, computational modeling of 71,756 RET variants for positive selection together with functional assays of 110 representative variants identified a three-dimensional cluster of VUSs carried by multiple human cancers that cause amino acid substitutions in the calmodulin-like motif (CaLM) of RET. Molecular dynamics simulations indicated that CaLM mutations decrease
more » ... ons between Ca2+ and its surrounding residues and induce conformational distortion of the RET cysteine-rich domain containing the CaLM. RET-CaLM mutations caused ligand-independent constitutive activation of RET kinase by homodimerization mediated by illegitimate disulfide bond formation. RET-CaLM mutants possessed oncogenic and tumorigenic activities that could be suppressed by tyrosine kinase inhibitors targeting RET. This study identifies calcium-binding ablating mutations as a novel type of oncogenic mutation of RET and indicates that in silico-driven annotation of VUSs of druggable oncogenes is a promising strategy to identify targetable driver mutations.
doi:10.1158/0008-5472.can-22-0834 pmid:36166639 pmcid:PMC9574375 fatcat:6rzpy7j5eje47ivscm22pmqxqq