Epidermal growth factor receptor and Human epidermal growth factor receptor 2 tyrosine kinase domains (EGFR/HER2)

The Epidermal growth factor receptor (EGFR) and Human epidermal growth factor receptor 2 (HER2) tyrosine kinase domains are the intracellular catalytic regions of these transmembrane receptors, belonging to the ErbB family of receptor tyrosine kinases [1, 2]. These domains are responsible for the phosphorylation of tyrosine residues, which triggers essential downstream signaling pathways such as MAPK/ERK and PI3K/Akt that regulate cell growth, survival, and metabolism [3, 4]. In many cancers, including breast, lung, and gastric malignancies, these domains are hyperactivated due to gene amplification or specific mutations, leading to uncontrolled cellular proliferation [5]. Small molecule tyrosine kinase inhibitors (TKIs) are designed to bind to the ATP-binding pocket within these domains, thereby blocking the catalytic activity and inhibiting oncogenic signaling [5, 6]. Dual inhibitors targeting both EGFR and HER2 are clinically significant as they can provide more comprehensive blockade of the ErbB signaling network and help overcome resistance mechanisms associated with single-receptor targeting [6]. However, therapeutic use is often limited by class-specific toxicities, such as severe diarrhea and skin rashes, resulting from the inhibition of these receptors in normal epithelial tissues [7]. Sources: [1] UniProt P00533; [2] UniProt P04626; [3] NIH NCI EGFR; [4] NIH NCI HER2; [5] StatPearls Tyrosine Kinase Inhibitors; [6] Nature Reviews Cancer (PMID: 16264488); [7] FDA Tykerb Label.

Other names

ErbB1/ErbB2 tyrosine kinase domainsHER1/HER2 tyrosine kinase domainsEGFR/ErbB2 tyrosine kinaseErbB family tyrosine kinase domains

ATP-competitive inhibition of the intracellular tyrosine kinase domains of EGFR and HER2, preventing receptor autophosphorylation and downstream signaling cascades.