1. Shedding Light on Mammalian Microautophagy
Tomer Shpilka, Zvulun Elazar 
Developmental Cell 
Volume 20, Issue 1, Pages 1-2 (January 2011)
DOI: /j.devcel
Copyright © 2011 Elsevier Inc. Terms and Conditions

2. Figure 1
Relationship between Chaperone-Mediated Autophagy and Microautophagy in Mammals
Sahu et al. (2011) describe a microautophagy-like process involving the formation of multivesicular bodies by isolated late endosomes as an alternative pathway for the degradation of KFERQ sequence motif containing protein in mammals. The molecular chaperone hsc70, thus, plays a key role in both this microautophagy-like pathway and chaperone-mediated autophagy by interacting with and targeting the KFERQ proteins to either the late endosome or the lysosome, respectively. In chaperone-mediated autophagy, hsc70 binds lysosome-associated membrane protein 2 (LAMP-2A) and mediates the unfolding of the KFERQ protein. The unfolded KFERQ protein then crosses the lysosomal membrane in a process mediated by LAMP-2A for degradation. In the microautophagy-like pathway described by Sahu et al. (2011), hsc70 binds the KFERQ protein, but its C-terminal positively charged residues direct the complex to phosphtidylserine in the late endosomal membrane. Subsequently, the KFERQ-protein is internalized into a vesicle, in an ESCRTI- and ESCRTIII-dependent manner. It is unclear whether hsc70 is also internalized into the vesicles as part of this process, and the molecular mechanism committing the chaperone to either pathway remains to be determined.
Developmental Cell  , 1-2DOI: ( /j.devcel )
Copyright © 2011 Elsevier Inc. Terms and Conditions