Protein unc-93 homolog B1 of the Major Facilitator Superfamily of transporters
Protein unc-93 homolog B1 (UNC93B1) controls intracellular trafficking and transport of a subset of Toll-like receptors (TLRs), including TLR3, TLR7 and TLR9, from the endoplasmic reticulum to endolysosomes where they can engage pathogen nucleotides and activate signaling cascades. It regulates differential transport of TLR7 and TLR9 into signaling endosomes to prevent autoimmunity. UNC93B1 belongs to the Unc-93 family of the Major Facilitator Superfamily (MFS) of transporters. MFS proteins are thought to function through a single substrate binding site, alternating-access mechanism involving a rocker-switch type of movement.
Feature 1:putative chemical substrate binding pocket [chemical binding site]
Evidence:
Comment:based on the structures of MFS transporters with bound substrates, substrate analogs, and/or inhibitors
Comment:since MFS proteins facilitate the transport of many different substrates including ions, sugar phosphates, drugs, neurotransmitters, nucleosides, amino acids, and peptides, the residues involved in substrate binding may not be strictly conserved among superfamily members
Comment:the substrate binding site or translocation pore has access to both sides of the membrane in an alternating fashion through a conformational change of the MFS transporter
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