MFS efflux transporter; part of the inp gene cluster that mediates the biosynthesis of fellutamide B, a mycotoxin that acts as a proteasome inhibitor (PubMed:20952652, PubMed:27294372). In the first step of fellutabmide B biosynthesis inpC activates 3-hydroxydodecanoic acid to generate 3-hydroxydodecanoyl-AMP that is then loaded onto the T0 domain of inpB (PubMed:27294372). The 3-hydroxydodecanoyl-S-phosphopantetheinyl-T0 is sequentially extended with L-Asn and L-Gln by the two CAT modules of inpB (PubMed:27294372). The linear lipodipeptide from inpB is then transferred onto inpA for the addition of the third amino acid, L-Leu (PubMed:27294372). Reductive releasing of the lipotripeptide by the TE domain of inpA produces (2S)-fellutamide B (PubMed:27294372). InpF might be involved in the release and transfer of the lipodipeptide from inpB to inpA (PubMed:27294372). The inp cluster-encoded proteasome subunit inpE confers resistance to internally produced fellutamides (PubMed:27294372). The MFS efflux transporter inpD may contribute to fellutamide resistance as well (PubMed:27294372). Expression is positively regulated by the secondary metabolism cross-pathway regulator scpR (PubMed:20952652). Does not affect production of fellutamides (PubMed:27294372). Belongs to the major facilitator superfamily.