Bifunctional inositol kinase that acts in concert with the IP6K kinases to synthesize the diphosphate group-containing inositol pyrophosphates diphosphoinositol pentakisphosphate, PP-InsP5, and bis-diphosphoinositol tetrakisphosphate, (PP)2-InsP4. Phosphorylates inositol hexakisphosphate (InsP6) at position 1 to produce PP-InsP5 which is in turn phosphorylated by IP6Ks to produce (PP)2-InsP4. Alternatively, phosphorylates PP-InsP5 at position 1, produced by IP6Ks from InsP6, to produce (PP)2-InsP4. Required for maintaining cellular integrity, normal growth and interactions with the ARP complex. Acts as a regulator of the PHO80-PHO85 cyclin/cyclin-dependent kinase (CDK) complex, thereby regulating signaling of phosphate availability. Required for the function of the cortical actin cytoskeleton, possibly by participating in correct F-actin localization and ensuring polarized growth. Regulates polarized growth and modulates interphase microtubule cytoskeleton. Regulates microtubule dynamics without the requirement of microtubule plus-end tracking protein Mal3. Required for growth zone selection 