PLCG1 (phospholipase C Gamma 1) is a core protein controlling various cell signaling pathways such as those related to immune response, cell proliferation, and apoptosis. In its natural state, PLCG1 is autoinhibited via interactions between its C2, cSH2, sPH, and TIM barrel domains, and must be phosphorylated by tyrosine kinases to change into its structurally active form. Activation of PLCG1 allows for hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) into inositol 1,4,5-trisphosphate (IP3), as well as the formation of diacylglycerol (DAG), which work together to trigger the desired response by utilizing calcium flow. Due to its heavily important role in cell signaling, mutations in PLCG1 have frequently been correlated with cancer, inflammation, and neurodegenerative diseases. To better understand the change in structure and function of these mutated proteins, four of the most common mutant strains (S345F, R48W, E1163K, and R687W) were designed with site-directed mutagenesis and purified through transfection of HEK 293T mammalian cells. In agreement with previous studies, results from TIRF microscopy found the S345F and E1163K variants to be gain-of-function mutations, while R48W and R687W mutants displayed similar activity and recruitment as the wild-type. These results highlight the importance of identifying mutations in PLCG1 and imply that S345F and E1163K mutations directly affect the autoinhibitory mechanism of PLCG1, causing unregulated activity and overexpression.
Ren et al. (Sun,) studied this question.