Kinase Membrane Preparations
Background of Kinase
Protein kinases are important regulators in practically every aspect of cell biology, and they have the ability to change the activity of a protein in almost any way. Protein phosphorylation can change the activity of enzymes as well as other biological processes like transcription and translation. Furthermore, some phosphorylation sites on a protein are stimulating, while others are inhibiting. There are 518 members of the human protein kinase gene family, as well as 106 pseudogenes. All protein kinases have a resting state and are only activated as needed by various regulatory cues. Switching between dormant and active protein kinases is a complicated process.
Fig.1 (A) The protein kinase A-phosphorylase kinase signal transduction cascade. (B) The EGFR mixed protein kinase cascade with protein-tyrosine, proteinserine/threonine, and dual specificity protein kinase participants. (Roskoski, 2015)
Application of Kinase Membranes
Drug development has been transformed by the introduction of membrane ligand binding assays and high-throughput screening. Ligand binding assays allow us to see how a ligand or a new synthetic molecule interacts with a target protein and assess affinity and kinetics of those interactions, while HTS helps to automate research and shorten development time.
Published Data
| Paper Title | FBXL2 counteracts Grp94 to destabilize EGFR and inhibit EGFR-driven NSCLC growth |
| Journal | Nature Communications |
| Published | 2021 |
| Abstract | Epidermal growth factor receptor (EGFR) abnormal activation promotes the growth of non-small cell lung cancer (NSCLC). Tyrosine-kinase inhibitor (TKI) resistance brought on by EGFR mutations is a significant barrier to treating NSCLC. Here, researchers demonstrate that EGFR and EGFR TKI-resistant mutants are targeted by the F-box protein FBXL2 for proteasome-mediated degradation, which inhibits the growth of EGFR-driven NSCLC. Patients with NSCLC who have reduced FBXL2 expression tend to have worse clinical outcomes. Furthermore, they demonstrate that Grp94, which blocks FBXL2 from binding to EGFR, shields EGFR from degradation. Additionally, researchers have discovered nebivolol, a small molecule inhibitor that is clinically used, which can increase FBXL2 expression to inhibit EGFR-driven NSCLC growth. Nebivolol has potent inhibitory effects on osimertinib-resistant NSCLC when combined with the drug or with Grp94-inhibitor-1. Together, these findings show that the FBXL2-Grp94-EGFR axis is essential for the growth of NSCLC and imply that FBXL2-Grp94 targeting to destabilize EGFR may be a potential therapeutic approach for TKI-resistant NSCLC. |
| Result |
Their findings compelled us to confirm the clinical significance of FBXL2 and EGFR in NSCLC. Even in cancer samples with EGFR gene mutations, analyses of the TCGA database revealed that FBXL2 expression was significantly reduced in non-small cell lung cancer (NSCLC). In addition, analyses of tissue microarrays (TMA) revealed that 66.67% (50 of 75) of human lung squamous cell carcinoma (LUSC) had low levels of FBXL2 expression compared to adjacent tissues. FBXL2 expression was similarly reduced in lung tumor samples derived from Rosa26-LSL-EGFRL858R/T758M mice. They investigated the expression of FBXL2 at various stages of human lung adenocarcinoma (LUAD). TMA analyses revealed that FBXL2 was gradually diminished during the progression of lung adenocarcinoma. In addition, a negative correlation was observed between FBXL2 and EGFR protein expression in lung adenocarcinoma and lung squamous cell carcinoma TMA samples. Low FBXL2 expression was consistently inversely correlated with high EGFR expression in the NSCLC cell lines used in this study. Moreover, analyses of Kaplan-Meier survival datasets revealed a correlation between low FBXL2 expression and poor overall survival (OS).
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Fig.2 FBXL2 inhibits EGFR-overexpressed or EGFRL858R/T790M-driven NSCLC growth and the expression of FBXL2 and EGFR is reversely correlated. (Niu, 2021)
References
- Roskoski Jr, R. A historical overview of protein kinases and their targeted small molecule inhibitors. Pharmacological research. 2015, 100: 1-23.
- Niu, M.M.; et al. FBXL2 counteracts Grp94 to destabilize EGFR and inhibit EGFR-driven NSCLC growth. Nature Communications. 2021, 12: 5919.
