Difference between revisions of "Phosphatase Subfamily PPIP5K"
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[[Phosphatase classification|Phosphatase Classification]]: [[Phosphatase_Fold_HP|Fold HP]]: [[Phosphatase_Superfamily_HP|Superfamily HP]] (histidine phosphatase): [[Phosphatase_Family_HP2|Family HP, branch 2]]: [[Phosphatase_Subfamily_PPIP5K|PPIP5K]] | [[Phosphatase classification|Phosphatase Classification]]: [[Phosphatase_Fold_HP|Fold HP]]: [[Phosphatase_Superfamily_HP|Superfamily HP]] (histidine phosphatase): [[Phosphatase_Family_HP2|Family HP, branch 2]]: [[Phosphatase_Subfamily_PPIP5K|PPIP5K]] | ||
| + | PPIP5K has a pseudophosphatase domain which bind to PtdIns(3,4,5)P3 and a kinase domain of RimK superfamily. The proteins therefore show kinase activity which convert InsP6 and 5-InsP7 to 1-InsP7 and InsP8. | ||
=== Evolution === | === Evolution === | ||
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=== Domain === | === Domain === | ||
| − | PPIP5K has two domains: N-terminal RimK/ATP-grasp domain | + | PPIP5K has two domains: N-terminal RimK/ATP-grasp domain, and C-terminal HP2 domain <cite>fridy07</cite>. |
| − | === | + | RimK/ATP-grasp domain confer PPIP5K's kinase activity that converts InsP6 and 5-InsP7 to 1-InsP7 and InsP8 <cite>fridy07, choi07</cite>. |
| − | + | ||
| + | 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 <cite>gokhale13</cite>. | ||
| + | |||
| + | === Catalytic activity and functions === | ||
| + | As mentioned above, the phosphatase domain of PPIP5K, HP2 domain, is catalytically inactive <cite>gokhale13</cite>. Because the kinase domain is active, the proteins show kinase activity in general. In particular, human PPIP5K1 and PPIP5K2 mediates phosphorylation of InsP6 and 5-InsP7 to 1-InsP7 and InsP8. InsP7 and InsP8 are multifunctional signaling molecules that regulate diverse cellular activities <cite>fridy07, choi07</cite>. | ||
| + | |||
| + | === References === | ||
| + | <biblio> | ||
| + | #fridy07 pmid=17690096 | ||
| + | #choi07 pmid=17702752 | ||
| + | #gokhale13 pmid=23682967 | ||
| + | </biblio> | ||
Revision as of 03:56, 2 January 2015
Phosphatase Classification: Fold HP: Superfamily HP (histidine phosphatase): Family HP, branch 2: PPIP5K
PPIP5K has a pseudophosphatase domain which bind to PtdIns(3,4,5)P3 and a kinase domain of RimK superfamily. The proteins therefore show kinase activity which convert InsP6 and 5-InsP7 to 1-InsP7 and InsP8.
Evolution
PPIP5K is conserved across opisthokont. Human genome has three copies.
Domain
PPIP5K has two domains: N-terminal RimK/ATP-grasp domain, and C-terminal HP2 domain [1].
RimK/ATP-grasp domain confer PPIP5K's kinase activity that converts InsP6 and 5-InsP7 to 1-InsP7 and InsP8 [1, 2].
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 [3].
Catalytic activity and functions
As mentioned above, the phosphatase domain of PPIP5K, HP2 domain, is catalytically inactive [3]. Because the kinase domain is active, the proteins show kinase activity in general. In particular, human PPIP5K1 and PPIP5K2 mediates phosphorylation of InsP6 and 5-InsP7 to 1-InsP7 and InsP8. InsP7 and InsP8 are multifunctional signaling molecules that regulate diverse cellular activities [1, 2].
References
- Fridy PC, Otto JC, Dollins DE, and York JD. Cloning and characterization of two human VIP1-like inositol hexakisphosphate and diphosphoinositol pentakisphosphate kinases. J Biol Chem. 2007 Oct 19;282(42):30754-62. DOI:10.1074/jbc.M704656200 |
- Choi JH, Williams J, Cho J, Falck JR, and Shears SB. Purification, sequencing, and molecular identification of a mammalian PP-InsP5 kinase that is activated when cells are exposed to hyperosmotic stress. J Biol Chem. 2007 Oct 19;282(42):30763-75. DOI:10.1074/jbc.M704655200 |
- Gokhale NA, Zaremba A, Janoshazi AK, Weaver JD, and Shears SB. PPIP5K1 modulates ligand competition between diphosphoinositol polyphosphates and PtdIns(3,4,5)P3 for polyphosphoinositide-binding domains. Biochem J. 2013 Aug 1;453(3):413-26. DOI:10.1042/BJ20121528 |
