KRAS and colorectal cancer: Phosphorylation of extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (p-T202/Y204-ERK) by oncogenic forms of KRAS has also been associated with resistance to mTOR kinase inhibitors in colorectal cancer.30 HCT116 cells carry an oncogenic KRAS-G13D allele, but PAT4 knockdown did not reduce ERK phosphorylation (Figures 4c and d), suggesting that it does not act through ERK to regulate mTORC1.