Slc7a3, also known as CAT3 (cationic amino acid transporter 3), is a major L-arginine transporter belonging to the solute carrier family 7. It plays a crucial role in amino-acid-mediated metabolism, facilitating the entry of cationic amino acids (such as arginine, ornithine, and lysine) into cells, especially in the brain where it is selectively expressed [5,6]. Arginine is involved in multiple cellular functions like the production of urea, nitric oxide, and polyamines. Understanding Slc7a3 is important as it may impact normal cellular functions and disease-related processes [4].

In a gene knockout study, the deletion of Slc7a3 did not affect normal hematopoietic stem cells (HSCs) in steady-state or under stress, nor did it impact T-cell development, activation, or proliferation, or leukemia development driven by certain mutations. This suggests that while extracellular arginine is important for HSCs, the CAT3 transporter encoded by Slc7a3 is dispensable for normal hematopoiesis and leukemogenesis [2]. In breast cancer, knockdown of SLC7A3 in vitro led to increased cell proliferation and invasion, indicating that SLC7A3 may have inhibitory effects on breast cancer cell growth [3]. In osteosarcoma, SIRPA promotes metastasis via the "SP1 stabilization circle" and SLC7A3-mediated arginine uptake [1].

In conclusion, Slc7a3 is essential for arginine uptake in cells, influencing various biological processes. Gene knockout mouse models have revealed its dispensability in normal and malignant hematopoiesis but have also shown its significance in cancer-related processes such as breast cancer cell proliferation and osteosarcoma metastasis. These findings highlight the importance of Slc7a3 in understanding normal and disease-associated cellular functions.