The function of KRAS (KRas proto-oncogene, GTPase, Ensembl gene identifier ENSG00000133703) is as follows. Signal transducer in the Ras-MAPK signaling pathway that regulates cell proliferation and survival (PubMed:22711838, PubMed:23698361). Ras proteins bind GDP/GTP and possess intrinsic GTPase activity (PubMed:20949621, PubMed:39809765). Activates MAPK1/MAPK3 resulting in phosphorylation and ultimately degradation of GJA1 (By similarity). Plays a role in promoting oncogenic events by inducing transcriptional silencing of tumor suppressor genes (TSGs) in colorectal cancer (CRC) cells in a ZNF304-dependent manner (PubMed:24623306). Recognized by LZTR1 that mediates its ubiquitination by a BCR (BTB-CUL3-RBX1) E3 ubiquitin-protein ligase complex (PubMed:40934300). {ECO:0000250|UniProtKB:P08644, ECO:0000269|PubMed:20949621, ECO:0000269|PubMed:22711838, ECO:0000269|PubMed:23698361, ECO:0000269|PubMed:24623306, ECO:0000269|PubMed:39809765, ECO:0000269|PubMed:40934300}.