Phosphatidylinositol 3-phosphate binding protein; formation of a distinct complex with TORC1, induced by glutamine in dose-dependent manner, results in TORC1 activation, suggesting dual roles as both a glutamine sensor and a direct TORC1 activator; involved in leucine- and glutamine-responsive TORC1 activation, independent of the Gtr/Ego pathway; related to human PLEKHF1, a lysosomal membrane permeabilization regulator; contains a PtdIns3P binding FYVE domain; similar to Fab1p and Vps27p