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BioMed Research International
Volume 2014 (2014), Article ID 832704, 11 pages
http://dx.doi.org/10.1155/2014/832704
Review Article

The Role of the Selective Adaptor p62 and Ubiquitin-Like Proteins in Autophagy

Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Pázmány Péter sétány 1/C., Budapest 1117, Hungary

Received 4 April 2014; Revised 15 May 2014; Accepted 19 May 2014; Published 12 June 2014

Academic Editor: Ioannis P. Nezis

Copyright © 2014 Mónika Lippai and Péter Lőw. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The ubiquitin-proteasome system and autophagy were long viewed as independent, parallel degradation systems with no point of intersection. By now we know that these degradation pathways share certain substrates and regulatory molecules and show coordinated and compensatory function. Two ubiquitin-like protein conjugation pathways were discovered that are required for autophagosome biogenesis: the Atg12-Atg5-Atg16 and Atg8 systems. Autophagy has been considered to be essentially a nonselective process, but it turned out to be at least partially selective. Selective substrates of autophagy include damaged mitochondria, intracellular pathogens, and even a subset of cytosolic proteins with the help of ubiquitin-binding autophagic adaptors, such as p62/SQSTM1, NBR1, NDP52, and Optineurin. These proteins selectively recognize autophagic cargo and mediate its engulfment into autophagosomes by binding to the small ubiquitin-like modifiers that belong to the Atg8/LC3 family.