Kanchan Garai

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Apolipoprotein E gene (APOE) alleles may shift the onset of Alzheimer's disease (AD) through apoE protein isoforms changing the probability of amyloid-β (Aβ) accumulation. It has been proposed that differential physical interactions of apoE isoforms with soluble Aβ (sAβ) in brain fluids influence the metabolism of Aβ, providing a mechanism to account for(More)
Apolipoproteins E3 and E4, proteins with a molecular mass of 34.15 kDa, differ by a single amino acid change. ApoE4 contains an arginine residue at position 112, whereas apoE3 has a cysteine at this position. ApoE4 is the major risk factor for late-onset Alzheimer's disease, whereas apoE3, the common isoform, is neutral with respect to this disease. Here,(More)
Huntington disease is caused by mutational expansion of the CAG trinucleotide within exon 1 of the huntingtin (Htt) gene. Exon 1 spanning N-terminal fragments (NTFs) of the Htt protein result from aberrant splicing of transcripts of mutant Htt. NTFs typically encompass a polyglutamine tract flanked by an N-terminal 17-residue amphipathic stretch (N17) and a(More)
Although amyloid β (Aβ) is a critical player in the pathology of Alzheimer's disease, there is currently little Information on the rate and extent of formation of oligomers that lead to the presence of Aβ fibrils observed in amyloid plaques. Here we describe a unique method to monitor the full time course of Aβ aggregation. In this method, Aβ is labeled(More)
The apolipoprotein apoE plays a key role in cholesterol and lipid metabolism. There are three isoforms of this protein, one of which, apoE4, is the major risk factor for Alzheimer's disease. At micromolar concentrations all lipid-free apoE isoforms exist primarily as monomers, dimers, and tetramers. However, the molecular weight form of apoE that binds to(More)
Apolipoprotein E (apoE) isoforms are known to differentially accumulate in the lysosomes of neuronal cells, and the deleterious effects of the apoE4 isoform in Alzheimer's disease may relate to its properties at the low lysosomal pH. However, the effect of pH on the molecular properties of full-length apoE is unclear. Here we examine the pH dependence of(More)
Soluble oligomers and fibrillar deposits of amyloid beta (Abeta) are key agents of Alzheimer's disease pathogenesis. However, the mechanism of amyloid aggregation and its interaction with live cells still remain unclear requiring the preparation of large amounts of pure and different Abeta peptides. Here we describe an Escherichia coli expression system(More)
Deposition of amyloid-β (Aβ) in Alzheimer's disease (AD) is strongly correlated with the APOE genotype. However, the role of apolipoprotein E (apoE) in Aβ aggregation has remained unclear. Here we have used different apoE preparations, such as recombinant protein or protein isolated from cultured astrocytes, to examine the effect of apoE on the aggregation(More)
Apolipoprotein E, a 34 kDa protein, plays a key role in triglyceride and cholesterol metabolism. Of the three common isoforms (ApoE2, -3, and -4), only ApoE4 is a risk factor for Alzheimer's disease. All three isoforms of wild-type ApoE self-associate to form oligomers, a process that may have functional consequences. Although the C-terminal domain,(More)
The apolipoprotein E family consists of three major protein isoforms: apolipoprotein E4 (ApoE4), ApoE3, and ApoE2. The isoforms, which contain 299 residues, differ only by single-amino acid changes, but of the three, only ApoE4 is a risk factor for Alzheimer’s disease. At micromolar concentrations, lipid-free ApoE exists predominantly as tetramers. In more(More)