There are three known splice variants of Type Igamma phosphatidylinositol 4-phosphate 5-kinase (PIPkin Igamma): PIPkins Igamma87, Igamma90, and the most recently cloned (Giudici, M.L., Emson, P.C. and Irvine, R.F. (2004) A novel neuronal-specific splice variant of Type I phosphatidylinositol 4-phosphate 5-kinase isoform gamma. Biochem. J. 379, 489-496) PIPkin IgammaC (here called PIPkin Igamma93). Here, we have explored the subcellular localisation and mobility of Type I PIPkins in transfected cells by confocal microscopy and flourescence recovery after photobleaching. The unique behaviour shown by PIPkin Igamma93 is consistent with its suggested distinct function. Moreover, the markedly different localisation and mobility of active versus inactive PIPkin Igamma93 provide insights into the factors that dictate cellular targeting of Type Igamma PIPkins.