forkhead associated (FHA) domain found in protein phosphatase 1 regulatory inhibitor subunit 8 (PPP1R8) and similar proteins
PPP1R8, also called nuclear inhibitor of protein phosphatase 1 (NIPP-1), is an inhibitor subunit of the major nuclear protein phosphatase-1 (PP-1). It has RNA-binding activity but does not cleave RNA and may target PP-1 to RNA-associated substrates. It may also be involved in pre-mRNA splicing and binds DNA and might act as a transcriptional repressor. PPP1R8 seems to be required for cell proliferation. PPP1R8 contains an FHA domain that mediates interactions with threonine-phosphorylated maternal embryonic leucine zipper kinase (MELK). The FHA domain is a small phosphopeptide recognition module.
Comment:also based on structures of other FHA domains with bound phosphopeptide
Comment:GR at the C terminus of strand beta3, SRxH just preceding beta5, and motif SxNG (SxHG in this model) in the beta6-beta7 turn indicate a canonical mode of pThr recognition.
Comment:Conserved residues are involved in binding directly to the ligand backbone and phosphate group. Non-conserved residues may determine binding specificity.
Jiyao W et al.(2023). "The conserved domain database in 2023.",