MOSPD2 is an endoplasmic reticulum (ER)-anchored tether protein that mediates membrane contact sites (MCS) between the ER and multiple organelles. At the molecular level, MOSPD2 contains a Major Sperm Protein domain that binds FFAT (two phenylalanines in an acidic tract) motifs on organelle-bound proteins, enabling tethering of endosomes, mitochondria, and Golgi to the ER 1. Additionally, MOSPD2 forms ER-lipid droplet contacts through direct protein-membrane interaction via an amphipathic helix that recognizes lipid packing defects, contributing to lipid droplet homeostasis 2. Beyond organellar organization, MOSPD2 promotes migration of primary monocytes and neutrophils in response to chemokines by regulating signaling cascades downstream of chemokine receptor ligation 3. Clinically, MOSPD2 has emerging significance in inflammatory disease: MOSPD2 knockout mice show suppressed experimental autoimmune encephalomyelitis development with reduced inflammatory monocyte infiltration, and anti-MOSPD2 monoclonal antibodies effectively treat CNS inflammation 4. In cancer, MOSPD2 expression is elevated in metastatic breast cancer, and its silencing impairs cancer cell migration and lung metastasis 5. Finally, MOSPD2 has been identified as an autoantigen in bacterial-associated immune infertility 6.