Snx4, or sorting nexin 4, is a key protein in membrane recycling processes. It binds to phosphatidylinositol 3-phosphate (PI3P) and is involved in pathways such as autophagy and endosomal sorting, playing a significant role in maintaining cellular homeostasis [2,4,5,6]. Genetic models, like knockout mice, are valuable for studying its functions.

In a conditional Snx4 knockout (cKO) mouse model, SNX4 cKO synapses showed enhanced neurotransmission during train stimulation, with an increase in docked synaptic vesicles at the active zone and a decreased active zone length, indicating SNX4 is a negative regulator of synaptic vesicle docking and release [3]. In clear cell renal cell carcinoma (ccRCC), the mRNA and protein expression level of Snx4 was significantly lower in cancer tissues compared to normal tissues. Lower Snx4 expression was associated with higher histologic grade, male patients, and poorer prognosis. Snx4 also had a positive correlation with immune cell infiltrating levels and PD-L1 expression [1].

In conclusion, Snx4 is crucial for membrane recycling, autophagy, and endosomal sorting. Studies using KO/CKO mouse models have revealed its roles in synaptic function and in diseases like ccRCC, providing insights into its functions in normal and disease-related biological processes.