Neurodegeneration induces upregulation of Beclin 1.
Erlich, Shlomit, et al.
Autophagy, 2: 49-51 (2006)
2006
Show Abstract
Autophagy, a bulk degradation of subcellular constituents, is activated in normal cell growth and development, and represents the major pathway by which the cell maintains a balance between protein synthesis and protein degradation. Autophagy was documented in several neurodegenerative diseases, and under stress conditions the autophagic process can lead to cell death (type II programmed cell death). Beclin 1 is a Bcl-2 interacting protein that was previously found to promote autophagy. We have used Beclin 1 protein as a marker for autophagy following traumatic brain injury in mice. We demonstrated a dramatic elevation in Beclin 1 levels near the injury site. Interestingly Beclin 1 elevation starts at early stages post injury (4 h) in neurons and 3 days later in astrocytes. In both cell types it lasts for at least three weeks. Neuronal cells, but not astrocytes, that overexpress Beclin 1 may exhibit damaged DNA but without changes in nuclear morphology. These observations may indicate that not all the Beclin1 overexpressing cells will die. The elevation of Beclin 1 at the site of injury may represent enhanced autophagy as a mechanism to discard injured cells and reduce damage to cells by disposing of injured components. | 16874043
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Increased susceptibility of cytoplasmic over nuclear polyglutamine aggregates to autophagic degradation.
Iwata, Atsushi, et al.
Proc. Natl. Acad. Sci. U.S.A., 102: 13135-40 (2005)
2005
Show Abstract
CNS neurons are endowed with the ability to recover from cytotoxic insults associated with the accumulation of proteinaceous aggregates in mouse models of polyglutamine disease, but the cellular mechanism underlying this phenomenon is unknown. Here, we show that autophagy is essential for the elimination of aggregated forms of mutant huntingtin and ataxin-1 from the cytoplasmic but not nuclear compartments. Human orthologs of yeast autophagy genes, molecular determinants of autophagic vacuole formation, are recruited to cytoplasmic but not nuclear inclusion bodies in vitro and in vivo. These data indicate that autophagy is a critical component of the cellular clearance of toxic protein aggregates and may help to explain why protein aggregates are more toxic when directed to the nucleus. | 16141322
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