Bifunctional inositol pyrophosphate kinase and phosphatase; contains two conserved catalytic motifs, a PPIP5K kinase domain that phosphorylates inositol hexakis- and heptakisphosphate, and a PPIP5K phosphatase domain that preferentially hydrolyzes, 1PP-InsP5 and 1,5-InsP8; unique GAF domain channels PPase substrates to the active site; IP7 levels decrease during starvation, suggesting a role in Pi homeostasis; may regulate the dimorphic switch and function of the cortical actin cytoskeleton