Publications by authors named "Saptarshi Maji"

Copper plays a key role in host-pathogen interaction. We find that during Leishmania major infection, the parasite-harboring macrophage regulates its copper homeostasis pathway in a way to facilitate copper-mediated neutralization of the pathogen. Copper-ATPase ATP7A transports copper to amastigote-harboring phagolysosomes to induce stress on parasites.

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Article Synopsis
  • ATP7A and ATP7B are special proteins that help control how copper moves around in our body.
  • When there’s a lot of copper, ATP7A goes to one part of the cell, and ATP7B goes to another part to keep things balanced.
  • Scientists found that a helper protein called AP-1 is important for making sure these copper proteins go to the right places, and without it, the proteins can't work properly.
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In hepatocytes, the Wilson disease protein ATP7B resides on the trans-Golgi network (TGN) and traffics to peripheral lysosomes to export excess intracellular copper through lysosomal exocytosis. We found that in basal copper or even upon copper chelation, a significant amount of ATP7B persists in the endolysosomal compartment of hepatocytes but not in non-hepatic cells. These ATP7B-harbouring lysosomes lie in close proximity of ~10 nm to the TGN.

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Mutational inactivation of the P-type Cu-ATPase ATP7B interferes with its cellular functions to varying extent leading to varied cellular phenotypes. Wilson's disease (WD) primarily affects organs composed of polarized/differentiated epithelial cells. Therefore, phenotypic variability might differ depending on the polarization/differentiation of the cells.

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Stimuli-responsive cross-linked nanocarriers that can induce lysosomal cell death (LCD) lysosomal membrane permeabilization (LMP) represent a new class of delivery platforms and have attracted the attention of researchers in the biomedical field. The advantages of such cross-linked nanocarriers are as follows (i) they remain intact during blood circulation; and (ii) they reach the target site specific receptor-mediated endocytosis leading to the enhancement of therapeutic efficacy and reduction of side effects. Herein, we have synthesized a mannose-6-phosphate (M6P) based amphiphilic ABC type tri-block copolymer having two chains of FDA-approved poly(ε-caprolactone) (PCL) as the hydrophobic block, and poly(-(-nitrobenzyl)-L-cysteine) (NBC) acts as the photoresponsive crosslinker block.

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Mutation in ATP7B gene causes Wilson disease (WD) that is characterized by severe hepatic and neurological symptoms. ATP7B localizes at the trans-Golgi Network (TGN) transporting copper to copper-dependent enzymes and traffics in apically targeted vesicles upon intracellular copper elevation. To decode the cellular underpinnings of WD manifestation we investigated copper-responsive polarized trafficking and copper transport activity of 15 WD causing point mutations in ATP7B.

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Copper(I) is an essential metal for all life forms. Though Cu(II) is the most abundant and stable state, its reduction to Cu(I) via an unclear mechanism is prerequisite for its bioutilization. In eukaryotes, the copper transporter-1 (CTR1) is the primary high-affinity copper importer, although its mechanism and role in Cu(II) reduction remain uncharacterized.

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Copper (Cu) is essential for all life forms; however, in excess, it becomes toxic. Toxic properties of Cu are known to be utilized by host species against various pathogenic invasions. Leishmania, in both free-living and intracellular forms, exhibits appreciable tolerance toward Cu stress.

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The Wilson disease protein, ATP7B maintains copper (herein referring to the Cu ion) homeostasis in the liver. ATP7B traffics from trans-Golgi network to endolysosomes to export excess copper. Regulation of ATP7B trafficking to and from endolysosomes is not well understood.

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Copper is crucial for carrying out normal physiological functions in all higher life forms. Copper Transporter 1 (CTR1) is the high-affinity copper importer found in all eukaryotic organisms. The copper transporter family primarily comprises ~ six members (CTR1-6) and the related members share high sequence homology with CTR.

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We report [Ru(L)(η--cym)Cl] ( and ) and [Pt(L)(DMSO)Cl] ( and ) complexes, where L is a chelate imine ligand derived from chloroethylamine and salicylaldehyde () or o-vanillin (). The complexes were characterized by single-crystal X-ray diffraction and other analytical techniques. The H nuclear magnetic resonance data show that both the Ru(II) and Pt(II) complexes start forming the aquated complex within an hour.

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