Phosphatase Subfamily PPIP5K

Phosphatase Classification: Fold HP: Superfamily HP (histidine phosphatase): Family HP, branch 2: PPIP5K

Evolution

PPIP5K is conserved across opisthokont. Human genome has three copies.

Domain

PPIP5K has two domains: N-terminal RimK/ATP-grasp domain which encodes its kinase activity, and C-terminal HP2 domain [1]. Unlike other members of HP2 family which are protein or non-protein phosphatases, the HP2 domain of PPIP5K is not catalytically active. Instead, this HP2 domain is specialized for binding PtdIns(3,4,5)P3, as a partial PH (pleckstrin homology) consensus sequence is spliced into this HP2 domain [2].

Functions

Human PPIP5K1 and PPIP5K2 mediates phosphorylation of InsP6 and 5-InsP7 to 1-InsP7 and InsP8, which are multifunctional signaling molecules that regulate diverse cellular activities [1, 3].