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    Disruption of protein-folding in neuronal cells causes neurodegeneration, mental retardation


    Alessandra d'Azzo, PhDAlessandra d'Azzo, PhD

    Excess accumulation in brain cells of a fat molecule called GM1-ganglioside (GM1) disrupts the folding of newly assembled proteins into their proper shapes, triggering nerve degeneration and mental retardation in children. This finding by St. Jude investigators is published in the September 10 issue of Molecular Cell.

    The disease, called GM1 gangliosidosis disrupts the normal functioning of brain cells and causes them to self-destruct. The St. Jude discovery offers strong evidence for the cause of GM1 gangliosidosis in children.

    GM1 gangliosidosis is a lysosomal storage disorder, an inherited disease in which one or more enzymes in the lysosomes are defective. Lysosomes are the cell’s recycling centers, where proteins, fats and other molecules are broken down to their basic building blocks, which are then reused to make new molecules.

    The discovery identifies for the first time the endoplasmic reticulum (ER)—the cell’s protein processing factory—as the location of biochemical reactions leading to brain cell death in children with this disease.

    “Our finding is exciting because children with GM1 gangliosidosis are severely affected and their outlook is dismal,” said Alessandra d’Azzo, PhD, of Genetics and Tumor Cell Biology. “Now that we have a better understanding of what causes the damage, we may be able to design treatments that specifically remedy this problem. If this finding holds true for other lysosomal storage diseases, the impact could be especially fruitful.”

    d’Azzo is senior author of the Molecular Cell report, and former St. Jude senior research technician Alessandra Tessitore, PhD, is the first author of the paper.

    Other St. Jude authors of this work are Maria del Martin; Renata Sano; Yanjun Ma, PhD; Angela Ingrassia; and Linda Hendershot, PhD, all of Genetics and Tumor Cell Biology; and Linda Mann, Hartwell Center.

     

    Last update: October 2004