**FLVCR1**, or feline leukemia virus subgroup C cellular receptor 1, is a significant gene. It functions as a plasma-membrane choline transporter in mammals, facilitating the uptake of choline into cells, which is crucial for choline metabolism and the initiation of the Kennedy pathway for phospholipid synthesis [1,2]. FLVCR1 is also associated with maintaining mitochondrial homeostasis and is involved in multiple cellular activities such as proliferation, migration, and invasion in various cancer-related processes [1,2].

Genetic studies, especially knockout (KO) models, have been instrumental in understanding FLVCR1's role. Flvcr1 knockout mice are embryonic lethal, but this can be partially rescued by choline supplementation, indicating its essential role in choline-related biological processes [1]. In cancer research, loss-of-function experiments in cell lines have shown that FLVCR1 knockdown inhibits cell proliferation, migration, and invasion in esophageal squamous cell carcinoma, colorectal cancer, cervical cancer, osteosarcoma, and cholangiocarcinoma [1].

In summary, FLVCR1 is essential for choline metabolism and mitochondrial homeostasis. KO mouse models have demonstrated its critical role in embryonic development related to choline availability. In the context of cancer, loss-of-function studies have revealed its role in promoting the malignant phenotype of various cancer cells, providing potential therapeutic targets for cancer treatment.

References:

1. Kenny, Timothy C, Khan, Artem, Son, Yeeun, Hite, Richard K, Birsoy, Kıvanç. 2023. Integrative genetic analysis identifies FLVCR1 as a plasma-membrane choline transporter in mammals. In Cell metabolism, 35, 1057-1071.e12. doi:10.1016/j.cmet.2023.04.003. https://pubmed.ncbi.nlm.nih.gov/37100056/

2. Son, Yeeun, Kenny, Timothy C, Khan, Artem, Birsoy, Kıvanç, Hite, Richard K. 2024. Structural basis of lipid head group entry to the Kennedy pathway by FLVCR1. In Nature, 629, 710-716. doi:10.1038/s41586-024-07374-4. https://pubmed.ncbi.nlm.nih.gov/38693265/