Repressor of jasmonate responses. Jasmonoyl-isoleucine (JA-Ile) specifically promotes COI1-TIFY6B/JAZ3 interaction. Acts as a negative regulator of MYC2 function. Feed-back regulated by MYC2. Homo- and heterodimer. Interacts with COI1, MYC2, MYC3, MYC4, TIFY10A/JAZ1, TIFY10B/JAZ2, TIFY6A/JAZ4, TIFY5A/JAZ8, TIFY7/JAZ9, TIFY9/JAZ10 and TIFY3A/JAZ11. Interacts (via TIFY domain) with AFPH2/NINJA. A number of isoforms are produced. According to EST sequences. Srtongly expressed in root tips. Up-regulated by jasmonate, wounding and herbivory. The tify domain is required for homo- and heterodimerization and for the interaction with other TIFY proteins. The jas domain (302-326) is necessary and sufficient for the hormone dependent interaction with COI1 and the hormone independent interaction with MYC2. Ubiquitinated. Targeted for degradation by the SCF(COI1) E3 ubiquitin ligase-proteasome pathway during jasmonate signaling. Belongs to the TIFY/JAZ family. PubMed:17637675 showed that COI1 interacts with the N-terminal part of the protein (1-208), but not with its C terminus. Truncated N-terminus.