Acts as a transcriptional repressor. Negative regulator of jasmonate responses. Connects the JAZ proteins and the non-JAZ protein TIFY8 with the TOPLESS corepressors. Component of a complex at least composed of TOPLESS, TPR2, TPR3, TIFY4B/PPD2, MYC3/ATR2 and TIFY3B/JAZ12. Interacts (via C-terminus) with TIFY10A/JAZ1; TIFY10B/JAZ2; TIFY6B/JAZ3; TIFY6A/JAZ4; TIFY11A/JAZ5; TIFY11B/JAZ6; TIFY7/JAZ9; TIFY9/JAZ10; TIFY3A/JAZ11; TIFY3B/JAZ12; TIFY4A/PPD1; TIFY4B/PPD2 and TIFY8 (via TIFY domain). Interacts with TOPLESS (PubMed:20360743, PubMed:24416306). Interacts with PAT1H1 (PubMed:26956135). By jasmonate. Unlike the JAZ proteins, the stability of AFPH2/NINJA is unaffected by jasmonate. Belongs to the Ninja family.