SUMMARY PARAGRAPH for DDP1
DDP1 encodes a polyphosphate phosphatase that hydrolyzes inositol pyrophosphates (PP-IPs) and diadenosine polyphosphates (ApAs) (3, 2). PP-IPs and ApAs are metabolically unrelated classes of signaling molecules that are important for processes such as vacuolar biogenesis, DNA repair, cell wall synthesis, telomere maintenance, phosphate homeostasis, stress responses, cell proliferation, and ion-channel function (reviewed in 1 and 3 and references therein). As a PP-IP phosphatase, Ddp1p dephosphorylates both bis-diphosphoinositol tetrakisphosphate ([PP]2-IP4, IP8) and diphosphoinositol pentakisphosphate (PP-IP5, IP7) down to inositol hexakisphosphate (IP6) (3). As an ApA phosphatase, Ddp1p dephosphorylates diadenosine hexaphosphate (Ap6A) most readily, but can also dephosphorylate diadenosine pentaphosphate (Ap5A), adenosine pentaphosphate (p5A), and adenosine tetraphosphate (p4A) (2).
Ddp1 is a member of the MutT motif (nudix hydrolase) family of enzymes that is conserved from yeast to human (2). Homologs include fission yeast APS1 and human DIPP (2, 3 and references therein).
Last updated: 2008-04-30