PMCC PMCC

Search tips
Search criteria

Advanced
Results 1-2 (2)
 

Clipboard (0)
None

Select a Filter Below

Journals
Authors
more »
Year of Publication
Document Types
1.  p62, Ref(2)P and ubiquitinated proteins are conserved markers of neuronal aging, aggregate formation and progressive autophagic defects 
Autophagy  2011;7(6):572-583.
Suppression of macroautophagy, due to mutations or through processes linked to aging, results in the accumulation of cytoplasmic substrates that are normally eliminated by the pathway. This is a significant problem in long-lived cells like neurons, where pathway defects can result in the accumulation of aggregates containing ubiquitinated proteins. The p62/Ref(2)P family of proteins is involved in the autophagic clearance of cytoplasmic protein bodies or sequestosomes. These unique structures are closely associated with protein inclusions containing ubiquitin as well as key components of the autophagy pathway. In this study we show that detergent fractionation followed by western blot analysis of insoluble ubiquitinated proteins (IUP), mammalian p62 and its Drosophila homologue, Ref(2)P can be used to quantitatively assess the activity level of aggregate clearance (aggrephagy) in complex tissues. Using this technique we show that genetic or age-dependent changes that modify the long-term enhancement or suppression of aggrephagy can be identified. Moreover, using the Drosophila model system this method can be used to establish autophagy-dependent protein clearance profiles that are occurring under a wide range of physiological conditions including developmental, fasting and altered metabolic pathways. This technique can also be used to examine proteopathies that are associated with human disorders such as frontotemporal dementia, Huntington and Alzheimer disease. Our findings indicate that measuring IUP profiles together with an assessment of p62/Ref(2)P proteins can be used as a screening or diagnostic tool to characterize genetic and age-dependent factors that alter the long-term function of autophagy and the clearance of protein aggregates occurring within complex tissues and cells.
doi:10.4161/auto.7.6.14943
PMCID: PMC3127048  PMID: 21325881
p62; Ref(2)P; insoluble ubiquitinated proteins; aggregates; neural degeneration; Alzheimer disease; aging; macroautophagy
2.  The selective macroautophagic degradation of aggregated proteins requires the phosphatidylinositol 3-phosphate binding protein Alfy 
Molecular cell  2010;38(2):265-279.
There is growing evidence that macroautophagic cargo is not limited to bulk cytosol in response to starvation, and can occur selectively for substrates including aggregated proteins. It remains unclear, however, if starvation-induced and selective macroautophagy share identical adapter molecules to capture their cargo. Here we report that Alfy, a phosphatidylinositol 3-phosphate binding protein, is central to the selective elimination of aggregated proteins. We report that the loss of Alfy inhibits the clearance of inclusions, with little to no effect on the starvation response. Alfy is recruited to intracellular inclusions and scaffolds a complex between p62(SQSTM1)-positive proteins and the autophagic effectors Atg5, Atg12, Atg16L and LC3. Alfy overexpression leads to elimination of aggregates in an Atg5-dependent manner, and likewise, to protection in a neuronal and Drosophila model of polyglutamine toxicity. We propose that Alfy plays a key role in selective macroautophagy, by bridging cargo to the molecular machinery that builds autophagosomes.
doi:10.1016/j.molcel.2010.04.007
PMCID: PMC2867245  PMID: 20417604

Results 1-2 (2)