Copper Stimulates Endocytosis of the Prion Protein

Pauly, Peter C.; Harris, David A.

doi:10.1074/jbc.273.50.33107

Cited by 559 publications

(485 citation statements)

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“…Interestingly, at the synaptic cleft, Cu 2+ regulation by binding to PrP c has been associated with the regulation of redox levels to facilitate neural transmission (Brown et al, 1997a;Herms et al, 1999). However, PrP c functions appear to be more diverse than a single redox control by PrP c -Cu 2+ binding in the cell or in the synapse, since PrP c -Cu 2+ in vitro binding promotes clathrin-mediated endocytosis (Cheng et al, 2006;Haigh et al, 2005;Pauly and Harris, 1998). This observation suggests that PrP c or PrP c -Cu 2+ binding is involved in the turnover of several receptors at the plasma membrane.…”

Section: Prp C Andmentioning

confidence: 99%

New insights into cellular prion protein (PrPc) functions: The “ying and yang” of a relevant protein

Nicolas

Gavı́n

Rı́o

2009

Brain Research Reviews

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Section: Prp C Andmentioning

confidence: 99%

New insights into cellular prion protein (PrPc) functions: The “ying and yang” of a relevant protein

Nicolas

Gavı́n

Rı́o

2009

Brain Research Reviews

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“…of PrP C is unknown, but recent investigations focus on the ability of the octarepeat domain to take up copper (5,(7)(8)(9)(10)(11). PrP C protects against apoptosis (12) and radical-mediated oxidative damage (13,14) and even stimulates nerve cell growth and development (15).…”

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confidence: 99%

The Affinity of Copper Binding to the Prion Protein Octarepeat Domain: Evidence for Negative Cooperativity

2006

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The prion protein (PrP) binds Cu 2+ in its N-terminal octarepeat domain, composed of four or more tandem PHGGGWGQ segments. Previous work from our laboratory demonstrates that copper interacts with the octarepeat domain through three distinct coordination modes at pH 7.4, depending upon the precise ratio of Cu 2+ to protein. Here, we apply both electron paramagnetic resonance (EPR) and fluorescence quenching to determine the copper affinity for each of these modes. At low copper occupancy, which favors multiple His coordination, the octarepeat domain binds Cu 2+ with a dissociation constant of 0.10 (±0.08) nM. In contrast, high copper occupancy, involving coordination through deprotonated amide nitrogens, exhibits a weaker affinity characterized by dissociation constants in the range of 7.0-12.0 μM. Decomposition of the EPR spectra reveals the proportions of all coordination species throughout the copper concentration range and identifies significant populations of intermediates, consistent with negative cooperativity. At most copper concentrations, the Hill coefficient is less than 1.0 and approximately 0.7 at half copper occupancy. These findings demonstrate that the octarepeat domain is responsive to a remarkably wide copper concentration range covering approximately 5 orders of magnitude. Consideration of these findings, along with the demonstrated ability of the protein to quench copper redox activity at high occupancy, suggests that PrP may function to protect cells by scavenging excess copper.The prion protein (PrP) 1 is responsible for a novel class of infectious, neurodegenerative diseases collectively known as the transmissible spongiform encephalopathies (TSEs) (1-3). The TSEs include scrapie in sheep, mad cow disease (bovine spongiform encephalopathy, BSE), chronic wasting disease (CWD) in deer and elk, and Creutzfeldt-Jakob disease (CJD) in humans. The normal cellular form of the prion protein, referred to as PrP C , is found in a wide range of tissues of all mammalian and avian species. A misfolding event converts the protein to the infectious, β-sheet-rich scrapie form (PrP Sc ) responsible for the TSEs.PrP C is a GPI-anchored glycoprotein expressed in abundance on the surface of neurons, predominantly on presynaptic membranes (4,5). The mature form of PrP, consisting of residues 23-231 in hamster, has a globular C-terminal domain and a largely unstructured N-terminal domain (6) (Figure 1). The C-terminal domain (residues 125-231) contains three α helices, two of which are stabilized by a single interhelical disulfide bond, and a small antiparallel β sheet. The flexible N-terminal domain is glycine-rich and highly flexible. Within the flexible N-terminal region of PrP is the octarepeat domain, composed of four or five highly conserved, contiguous repeats of the eight-residue sequence PHGGGWGQ. The physiological function

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“…It also seems that specific lateral associations of GPI-anchored proteins with other plasma membrane components could drastically influence their precise pathway of internalization. In the case of GPI-anchored prion proteins in neuronal cells, their amino-terminal domain specifies clathrin-pit localization, and this might be augmented by association of the prion protein with metal ions (Pauly and Harris, 1998;Sunyach et al, 2003). In recent studies, it has been shown that GPI-anchored prion protein (PrP C ) is enriched in caveolae at the plasma membrane, and a caveolar uptake mechanism for PrP C and its conversion to PrP sc was proposed.…”

Section: Introductionmentioning

confidence: 99%

Arf6-independent GPI-anchored Protein-enriched Early Endosomal Compartments Fuse with Sorting Endosomes via a Rab5/Phosphatidylinositol-3′-Kinase–dependent Machinery

Kalia

Kumari

Chadda

et al. 2006

MBoC

107

117

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In the process of internalization of molecules from the extracellular milieu, a cell uses multiple endocytic pathways, consequently generating different endocytic vesicles. These primary endocytic vesicles are targeted to specific destinations inside the cell. Here, we show that GPI-anchored proteins are internalized by an Arf6-independent mechanism into GPI-anchored protein-enriched early endosomal compartments (GEECs). Internalized GPI-anchored proteins and the fluid phase are first visualized in GEECs that are acidic, primary endocytic structures, negative for early endosomal markers, Rab4, Rab5, and early endosome antigen (EEA)1. They subsequently acquire Rab5 and EEA1 before homotypic fusion with other GEECs, and heterotypic fusion with endosomes containing cargo from the clathrin-dependent endocytic pathway. Although, the formation of GEECs is unaffected by inhibition of Rab5 GTPase and phosphatidylinositol-3 -kinase (PI3K) activity, their fusion with sorting endosomes is dependent on both activities. Overexpression of Rab5 reverts PI3K inhibition of fusion, providing evidence that Rab5 effectors play important roles in heterotypic fusion between the dynamin-independent GEECs and clathrin-and dynamin-dependent sorting endosomes. INTRODUCTIONA cell uses multiple endocytic pathways for the uptake of molecules from the extracellular milieu (Mukherjee et al., 1997;Conner and Schmid, 2003). The better characterized pathways are mediated by clathrin-and caveolae-coated endocytic invaginations and require dynamin activity to be severed from the plasma membrane (Damke et al., 1994;Hinshaw and Schmid, 1995;Henley et al., 1998;Oh et al., 1998). There also seem to be one or more clathrin-independent pathways where dynamin is required, for example, the pathway for internalization of the interleukin (IL)-2 receptor subunits (Lamaze et al., 2001). In addition, there are a growing number of dynamin-independent endocytic processes that serve as internalization routes for a number of cell surface proteins, including lipid-linked proteins, such as GPI-anchored proteins (Lamaze and Schmid, 1995;Conner and Schmid, 2003;Nichols, 2003;Mayor and Riezman, 2004;Naslavsky et al., 2004;.GPI-anchored proteins are internalized via a dynamin, caveolin, and clathrin-independent pathway that is also responsible for the entry of a sizable fraction of the fluid phase in a number of cell types (Fivaz et al., 2002;Sabharanjak et al., 2002;Guha et al., 2003;. GPI-anchored proteins and the fluid phase enter the cell via tubular invaginations at the cell surface, into compartments termed GPI-anchored protein-enriched early endosomal compartments (GEECs) . At early times, these structures are largely devoid of cargo from the clathrin-dependent pathway. Besides a requirement for the small GTPase cdc42, very little is known about the molecular players that govern the formation and trafficking of GEECs. Much less is known about the detailed endocytic itinerary of these pathways (Lamaze and Schmid, 1995;Mayor and Riezman, 2004).After internalization...

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Copper Stimulates Endocytosis of the Prion Protein

Cited by 559 publications

References 34 publications

New insights into cellular prion protein (PrPc) functions: The “ying and yang” of a relevant protein

New insights into cellular prion protein (PrPc) functions: The “ying and yang” of a relevant protein

The Affinity of Copper Binding to the Prion Protein Octarepeat Domain: Evidence for Negative Cooperativity

Arf6-independent GPI-anchored Protein-enriched Early Endosomal Compartments Fuse with Sorting Endosomes via a Rab5/Phosphatidylinositol-3′-Kinase–dependent Machinery

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