〔Abstract〕 To investigate whether TYRO protein tyrosine kinase-binding protein (TYROBP) affects the progression of diabetic kidney disease (DKD) through the extracellular signal-regulated kinase ( ERK) pathway. Methods Key genes in DKD were identified through bioinformatics analysis . Immunohistochemical staining and quantitative real-time PCR (qPCR) were used to validate the expression levels of TYROBP in a DKD mouse model and high glucose-stimulated NRK-52E cells . NRK-52E cell models with stable TYROBP overexpression/knockdown and their corresponding empty vector (ev) /scrambled sequence (ss) controls were established via lentiviral trans- fection . Cells were treated with 5 . 5 mmol/L or 30. 0 mmol/L glucose for 72 hours to mimic normal glucose (NG) and high glucose ( HG) conditions , respectively. High glucose medium containing 3 . 5 μmol/L FR180204 was used for ERK inhibitor intervention . The experiment included seven groups : ev + NG , ev + HG , oe-TYROBP + HG , ss + NG , ss + HG , sh-TYROBP + HG , and sh-TYROBP + HG + ERK inhibitor. Western blot was used to de- tect the expression levels of phosphorylated ERK/total ERK (p-ERK/ERK) , apoptosis-related proteins B-cell lym- phoma-2 (Bcl-2) and Bcl-2-associated X protein ( Bax) , and epithelial-mesenchymal transition ( EMT)-related proteins E-cadherin and α-smooth muscle actin ( α-SMA) . Tetramethylrhodamine ethyl ester (TMRE) staining and Annexin V-fluorescein isothiocyanate/propidium iodide (Annexin V-FITC/PI) flow cytometry were performed to as- sess mitochondrial membrane potential and apoptosis levels . Results Bioinformatics analysis identified TYROBP as a key gene in DKD . In vivo and in vitro validation showed increased TYROBP mRNA levels in DKD models . The results from the HG model indicated that , compared to the ev + NG/ss + NG group , the ev + HG/ss + HG group demonstrated increased p-ERK/ERK expression , reduced mitochondrial membrane potential , elevated apoptosis , and enhanced EMT. In TYROBP-perturbed NRK-52E cells , compared to the ev + HG group , the oe-TYROBP + HG group showed decreased p-ERK/ERK expression (P < 0. 01) , increased mitochondrial membrane potential (P < 0. 05) , reduced apoptosis (P < 0. 001) , and attenuated EMT; whereas compared to the ss + HG group , the sh- TYROBP + HG group exhibited increased p-ERK/ERK expression ( P < 0. 001) , decreased mitochondrial mem- brane potential (P < 0. 01) , elevated apoptosis (P < 0. 001) , and enhanced EMT. Furthermore , compared to the sh-TYROBP + HG group , the sh-TYROBP + HG + ERK inhibitor group displayed reduced p-ERK/ERK expression (P < 0. 01) , increased mitochondrial membrane potential ( P < 0. 001) , decreased apoptosis ( P < 0. 001) , and suppressed EMT. Compared with the scrambled sequence control + high glucose group , the TYROBP knockdown + high glucose group showed elevated p-ERK/ERK expression ( P < 0. 001) , reduced mitochondrial membrane potential (P < 0. 01) , increased apoptosis level (P < 0. 001) , and enhanced EMT. Compared with the TYROBP knockdown + high glucose group , the TYROBP knockdown + high glucose + ERK inhibitor group demonstrated decreased p-ERK/ERK expression (P < 0. 01) , restored mitochondrial membrane potential (P < 0. 001) , reduced apoptosis level (P < 0. 001) , and suppressed EMT. Conclusion TYROBP may regulate the ERK signaling path- way to modulate apoptosis- and EMT-related proteins , thereby influencing mitochondrial membrane potential , apop- tosis , and EMT in renal tubular epithelial cells and contributing to DKD progression .