homologous-pairing protein 2 homolog (proteasome 26S ATPase subunit 3-interacting protein, PSMC3-interacting protein, Tat-binding protein 1-interacting protein, TBP-1-interacting protein, nuclear receptor coactivator GT198, PSMC3IP, HOP2, TBPIP)

Function

• role in meiotic recombinaison
• stimulates the DMC1-mediated strand exchange required for matching homology within homologous chromosomes during meiosis
• forms stable heterodimer with MND1 (PSMC3IP/MND1) that:
  • binds DNA
  • stimulates the recombinase activity of DMC1 as well as DMC1 D-loop formation from double-strand DNA
  • stabilizes presynaptic RAD51 & DMC1 filaments formed on single strand DNA to capture double-strand DNA
  • stimulates both synaptic & presynaptic critical steps in RAD51 & DMC1-promoted homologous pairing
• may inhibit HIV-1 viral protein TAT activity & modulate the activity of proteasomes through association with PSMC3
• interacts with the DNA-binding domain of nuclear receptors NR3C1/GR, ESR2/ER-beta, THRB & RXRA (putative)
• interacts with PSMC3/TBP1
• phosphorylated by PKA, PKC & MAPK (putative)
• phosphorylated upon DNA damage, probably by ATM or ATR

Structure

belongs to the HOP2 family

Compartment

nucleus

Alternative splicing

named isoforms=2

Expression

highly expressed in testis & colon

Pathology

• overexpressed in leiomyomas compared to myometrium

More general terms

• receptor
• nuclear protein
• phosphoprotein

Database

• OMIM: https://mirror.omim.org/entry/608665
• UniProt: http://www.uniprot.org/uniprot/Q9P2W1.html