Phosphatidylinositol 3-phosphate binding protein; forms a distinct complex with TORC1, induced by glutamine in a dose-dependent manner, resulting in TORC1 activation, suggesting dual roles as both a glutamine sensor and a direct TORC1 activator; functions as a cysteine sensor involved in TORC1 activation; involved in leucine- and glutamine-responsive TORC1 activation, independent of the Gtr/Ego pathway; related to human PLEKHF1; contains a PI3P binding FYVE domain; similar to Fab1p and Vps27p