Sphingosine-1-phosphate (S1P) is a bioactive phospholipid that regulates many important cell processes such as proliferation, survival, apoptosis and migration. S1P production is catalysed by the sphingosine kinases (SKs), of which two mammalian isoforms exist, SK1 and SK2. The pro-survival and pro-proliferative functions of SK1 are well established. However, comparatively little is known about SK2 function and regulation, but it appears that SK2 can have both pro-survival and pro-apoptotic roles, seemingly dictated by its subcellular localisation. Interestingly, SK2 has emerged as a promising target for anti-cancer therapies, as elevated levels of SK2 have been detected in a number of human cancers, and an SK2-selective inhibitor is currently in human clinical trials to treat advanced solid tumours. Hence, it is of interest to understand the mechanisms that regulate the complex and opposing functions of SK2. To this end, a yeast two-hybrid screen was performed using human SK2 as bait, which identified DYNC1I2, a component of cytoplasmic dynein, as a SK2-interacting protein. Dynein is a microtubule-associated transport motor protein complex involved in retrograde organelle and protein transport, mitotic spindle orientation and cell migration. This interaction was confirmed in mammalian cells, verifying that SK2 physiologically interacts with components of the dynein-dynactin-microtubule complexes. Furthermore, data from immunofluorescence localisation studies suggest that cytoplasmic dynein is involved in the retrograde transport of SK2 within the cell. SK2 has been previously shown to promote apoptosis when localised to internal cellular compartments such as the nucleus, endoplasmic reticulum and mitochondria, whereas it promotes cell survival and proliferation at the plasma membrane. Therefore, by regulating SK2 localisation, cytoplasmic dynein may be a key regulator of the balance between the pro-cancer and pro-cell death roles of SK2.