The link between SACM1L and phosphoinositide methabolism

SACM1L is a uncharacterised human protein identified in a screen for cDNAs with potential to encode large proteins expressed in brain(Nagase et al. 2000). It is a homologue of yeast Sac1p and contains synaptojanin domain. Sac1p is a phosphatidylinositol 4- phosphatase involved in various cellular processes like actin cytoskeleton organization and Golgi trafficking (see review: Hughes et al. 2000). Synaptojanin is a presynaptic phosphatidylinositol 5 - phosphatase implicated in synaptic vesicle recycling (McPherson et al. 1996). Therefore it is possible that SACM1L regulates phospholipid metabolism in neuronal cells. It could exhibit the ability to dephosphorilate both 4- and 5- phosphate groups.