Members of the Atg8 protein family (1) are small proteins with a ubiquitin-like fold and are key components of the macroautophagy machinery, participating essentially in all steps of macroautophagy from phagophore nucleation, to autolysosome formation (2). They are involved in an increasing number of biological processes, including LC3-associated phagocytosis (3, 4), endosomal microautophagy (4, 5), and unconventional secretion (6).
In selective macroautophagy, selectivity is mainly achieved through receptor proteins that bind to the surface of Atg8 by anchoring a small linear peptide (AIM in plants and fungi, LIR-motif in mammals) (7). After the discovery of the first few LIR-containing proteins (LIRCPs), several definitions of the LIR-motif have appeared in the literature, highlighting a short core consensus sequence described by the regular expression pattern [WFY]xx[VLI] (8, 9, 10, 11, 12). Accumulating experimental evidence pinpoints the importance of regions flanking the core LIR-motif, while several instances of atypical LIR-motifs and LIR-independent interactions are being uncovered.
We have developed LIRcentral as a publicly available, comprehensive collection of experimentally confirmed LIR-motifs, based on extensive biomedical literature search, assisted by text mining techniques and careful manual curation. Interested researchers are able to retrieve information about literature-validated LIR-motifs and display them along with sequence features annotated in UniProt. A pre-print describing LIRcentral is available in bioRxiv.