Sphingosine kinase (SphK) is a class of lipid kinases, primarily consisting of two isoforms, SphK1 and SphK2, responsible for converting sphingosine to sphingosine-1-phosphate (S1P). SphK1 is mainly localized in the cytoplasm and plasma membrane, while SphK2 is found in the endoplasmic reticulum, mitochondria, and nucleus. SphK participates in regulating various biological processes such as cell proliferation, survival, migration, and inflammation by generating S1P, activating signaling pathways including PI3K/Akt, MAPK, and PLC. The specific expression and mutations of the SphK gene are associated with various diseases, including cancer, cardiovascular diseases, and immune system disorders, making it a potential target for treating these conditions.