serine/threonine protein phosphatase 4 (PP4)

Function: - protein phosphatase with role in: a) microtubule organization at centrosomes b) maturation of spliceosomal snRNPs c) apoptosis d) TNF-alpha signaling e) activation of c-Jun N-terminal kinase MAPK8 f) regulation of histone acetylation g) DNA damage checkpoint signaling h) NF-kappa-B activation i) cell migration - the PPP4C-PPP4R1 PP4 complex may play a role in dephosphorylation & regulation of HDAC3 - the PPP4C-PPP4R2-PPP4R3A PP4 complex specifically dephosphorylates H2AFX phosphorylated on Ser-140 (gamma-H2AFX) generated during DNA replication & required for DNA double-strand break repair - dephosphorylates NDEL1 at CDC2/Cdk1 phosphorylation sites & negatively regulates CDC2/Cdk1 activity in interphase (putative) Structure: - different assemblies of the catalytic & one or more regulatory subunits - PP4 complexes PPP4C-PPP4R1, PPP4C-PPP4R2, PPP4C-PPP4R2-PPP4R3A, PPP4C-PPP4R2-PPP4R3B & PPP4C-PPP4R4 - the PPP4C-PPP4R2 complex appears to be a tetramer composed of 2 molecules of catalytic subunit PPP4C & 2 molecules of the core regulatory subunit PPP4R2

General

molecular complex serine/threonine phosphatase

Properties

STATE: active state MOTIF: active site SUBUNITS: protein phosphatase 4 catalytic subunit MOTIF: Iron [Fe]-binding site SITE: 54-54 Iron [Fe]-binding site SITE: 56-56 Iron [Fe]-binding site SITE: 82-82 manganese [Mn]-binding site SITE: 114-114 histidine residue {H115} manganese [Mn]-binding site SITE: 164-164 manganese [Mn]-binding site SITE: 238-238 STATE: active state protein phosphatase 4 regulatory subunit 1 MOTIF: HEAT repeat {1-25} HEAT repeat {26-63} HEAT repeat {65-81} HEAT repeat {82-119} HEAT repeat {127-164} HEAT repeat {168-206} HEAT repeat {208-246} HEAT repeat {248-285} HEAT repeat {287-324} HEAT repeat {505-542} HEAT repeat {568-606} HEAT repeat {698-734} HEAT repeat {799-837} HEAT repeat {861-898}

References

UniProt :accession Q9NY27

Components

serine/threonine protein phosphatase 4 catalytic subunit; PP4C; Pp4; protein phosphatase X; PP-X (PPP4C, PPP4, PPX) serine/threonine protein phosphatase 4 regulatory subunit 1 (PPP4R1, PP4R1, MEG1)