Autophagy and p62/sequestosome 1 generate neo-antimicrobial peptides (cryptides) from cytosolic proteins

Abstract

In a manifestation of the immunological autophagy termed xenophagy, autophagic adapter proteins such as p62 and NDP52 directly capture microbes for delivery to autophagosomal organelles where they are eliminated. In a mirror image phenomenon, which is also an immunological variant of the process termed decryption, p62 and autophagy contribute to the elimination of Mycobacterium tuberculosis. During decryption, p62 sequesters cytosolic proteins into autophagosomes where they are proteolytically converted into peptides termed cryptides. A subset of cryptides possesses antimicrobial peptide properties exhibited upon their delivery to parasitophorous vacuoles where they kill intracellular microbes.

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Figures and Tables

Figure 1 Elimination of M. tuberculosis by autophagy and p62. Mycobacteria are phagocytosed by macrophages and at least for some time reside within phagosomes. Upon induction of autophagy, p62, as a bifunctional agent interacting with autophagic substrates and with LC3, recruits into autophagosomes pre-antimicrobicidal cytosolic substrates. Autophagosome maturation including acquisition of lysosomal hydrolases leads to the proteolytic cleavage of p62 substrates and their conversion into peptides (cryptides) that can act as antimicrobial peptides.

Punctum to: Ponpuak M, Davis AS, Roberts EA, Delgado MA, Dinkins C, Zhao Z, et al. Delivery of cytosolic components by p62 endows autophagosomes with unique anti-microbial properties. Immunity 2010; 32:329 - 341; PMID: 20206555; http://dx.doi.org/10.1016/j.immuni.2010.02.009

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