Human APP

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PDB ID 1mwp

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Human amyloid precursor protein heparin-binding domain, 1mwp
Resources: FirstGlance, OCA, RCSB, PDBsum
Coordinates: save as pdb, mmCIF, xml



Contents

Functions of human APP and Fe65 protein

There are suggestions that the binding of APP with Fe65 has been implicated in regulating cell motility and growth cone dynamics [1] [2]

APP is a cell surface receptor and performs physiological functions on the surface of neurons relevant to neurite growth, neuronal adhesion and axonogenesis. APP is involved in cell mobility and transcription regulation through protein-protein interactions. Can promote transcription activation through binding to APBB1-KAT5 and inhibits Notch signaling through interaction with Numb. Couples to apoptosis-inducing pathways such as those mediated by G(O) and JIP. Inhibits G(o) alpha ATPase activity By similarity. Acts as a kinesin I membrane receptor, mediating the axonal transport of beta-secretase and presenilin 1. Involved in copper homeostasis/oxidative stress through copper ion reduction. In vitro, copper-metallated APP induces neuronal death directly or is potentiated through Cu2+-mediated low-density lipoprotein oxidation. Can regulate neurite outgrowth through binding to components of the extracellular matrix such as heparin and collagen I and IV. The splice isoforms that contain the BPTI domain possess protease inhibitor activity.

Beta-amyloid peptides are lipophilic metal chelators with metal-reducing activity. Bind transient metals such as copper, zinc and iron. In vitro, can reduce Cu2+ and Fe3+ to Cu+ and Fe2+, respectively. Beta-amyloid 42 is a more effective reductant than beta-amyloid 40. Beta-amyloid peptides bind to lipoproteins and apolipoproteins E and J in the CSF and to HDL particles in plasma, inhibiting metal-catalyzed oxidation of lipoproteins. Beta-APP42 may activate mononuclear phagocytes in the brain and elicit inflammatory responses. Promotes both tau aggregation and TPK II-mediated phosphorylation. Interaction with overexpressed HADH2 leads to oxidative stress and neurotoxicity. [3] [4] [5] [6]


Fe65 is an adaptor protein localized in the nucleus. It interacts with the Alzheimer's disease amyloid precursor protein (APP), transcription factor CP2/LSF/LBP1 and the low-density lipoprotein receptor-related protein. APP functions as a cytosolic anchoring site that can prevent the gene product's nuclear translocation. This encoded protein could play an important role in the pathogenesis of Alzheimer's disease. It is thought to regulate transcription. Also it is observed to block cell cycle progression by downregulating thymidylate synthase expression. Multiple alternatively spliced transcript variants have been described for this gene but some of their full length sequence is not known.[provided by RefSeq].[7]

Fe65 plays a central role in the response to DNA damage by translocating to the nucleus and inducing apoptosis. May act by specifically recognizing and binding histone H2AX phosphorylated on 'Tyr-142' (H2AXY142ph) at double-strand breaks (DSBs), recruiting other pro-apoptosis factors such as MAPK8/JNK1.Required for histone H4 acetylation at double-strand breaks (DSBs).Its ability to specifically bind modified histones and chromatin modifying enzymes such as KAT5/TIP60, probably explains its trancription activation activity. [8]

Location

Fe65 could be located in cell membrane, cytoplasm, nucleus. In normal conditions, it mainly localizes to the cytoplasm, while a small fraction is tethered to the cell membrane via its interaction with APP. Following exposure to DNA damaging agents, it is released from cell membrane and translocates to the nucleus. Nuclear translocation is under the regulation of APP.[9]


Cell surface protein that rapidly becomes internalized via clathrin-coated pits. During maturation, the immature APP (N-glycosylated in the endoplasmic reticulum) moves to the Golgi complex where complete maturation occurs (O-glycosylated and sulfated). After alpha-secretase cleavage, soluble APP is released into the extracellular space and the C-terminal is internalized to endosomes and lysosomes. Some APP accumulates in secretory transport vesicles leaving the late Golgi compartment and returns to the cell surface. Gamma-CTF(59) peptide is located to both the cytoplasm and nuclei of neurons. It can be translocated to the nucleus through association with APBB1 (Fe65). Beta-APP42 associates with FRPL1 at the cell surface and the complex is then rapidly internalized. APP sorts to the basolateral surface in epithelial cells. During neuronal differentiation, the Thr-743 phosphorylated form is located mainly in growth cones, moderately in neurites and sparingly in the cell body. Casein kinase phosphorylation can occur either at the cell surface or within a post-Golgi compartment [10]

APP and Alzheimer's disease

Aβ peptides are generated in neuronal secretory vesicles by proteolytic cleavage of the amyloid precursor protein (APP) by proteases, called β-secretase and γ-secretase that cleave at the N-terminus and variant C-termini of Aβ within APP, respectively, resulting in Aβ of 40 or 42 amino acids (Aβ40 and Aβ42, respectively) (Figure 1). Because the N-termini of Aβ40 and Aβ42 are identical, development of inhibitors that reduce cleavage of APP at the β-secretase site are likely to be effective for reducing Aβ peptide forms with alleviation of neurodegeneration and memory deficit. The APP in the vast majority of AD patients possesses the wild-type β-secretase site sequence. [11]

3D structures of human APP

Amyloid precursor protein

Additional Resources

For additional information, see: Alzheimer's Disease

References

1. Radzimanowski J, Simon B, Sattler M, Beyreuther K, Sinning I, Wild K. (2008) Structure of the intracellular domain of the amyloid precursor protein in complex with Fe65-PTB2. Embo Rep. v9 pp. 1134-40. PMID 18833287

2. Radzimanowski J, Simon B, Sattler M, Beyreuther K, Sinning I, Wild K. (2008) Structure of the intracellular domain of the amyloid precursor protein in complex with Fe65-PTB2. Embo Rep. v9 pp. 1134-40. PMID 18833287

3. Ando K, Iijima KI, Elliott JI, Kirino Y, Suzuki T. Phosphorylation-dependent regulation of the interaction of amyloid precursor protein with Fe65 affects the production of beta-amyloid.J Biol Chem. 2001 Oct 26;276(43):40353-61. Epub 2001 Aug 21. PMID: 11517218

4. Sabo SL, Ikin AF, Buxbaum JD, Greengard P. The Alzheimer amyloid precursor protein (APP) and FE65, an APP-binding protein, regulate cell movement. J Cell Biol. 2001;153:1403–1414. [PubMed Sabo SL, Ikin AF, Buxbaum JD, Greengard P. The Alzheimer amyloid precursor protein (APP) and FE65, an APP-binding protein, regulate cell movement. J Cell Biol. 2001;153:1403–1414. [PubMed PMID: 11425871

5. Sabo SL, Ikin AF, Buxbaum JD, Greengard P. The amyloid precursor protein and its regulatory protein, FE65, in growth cones and synapses in vitro and in vivo. J Neurosci. 2003;23:5407–5415. [PubMed] 12843239

6. "Alzheimer's disease amyloid beta peptide 25-35 inhibits lipid peroxidation as a result of its membrane interactions." Walter M.F., Mason P.E., Mason R.P. Biochem. Biophys. Res. Commun. 233:760-764(1997) [PubMed: 9168929] [Abstract] Cited for: FUNCTION OF BETA-AMYLOID PEPTIDE AS LIPID PEROXIDATION INHIBITOR, MUTAGENESIS OF MET-706.

7. "The intracellular domain of the beta-amyloid precursor protein is stabilized by Fe65 and translocates to the nucleus in a notch-like manner." Kimberly W.T., Zheng J.B., Guenette S.Y., Selkoe D.J. J. Biol. Chem. 276:40288-40292(2001) [PubMed: 11544248] [Abstract] Cited for: INTERACTION WITH APBB1, FUNCTION, SUBCELLULAR LOCATION.

8. "Direct interaction of soluble human recombinant tau protein with Abeta 1-42 results in tau aggregation and hyperphosphorylation by tau protein kinase II." Rank K.B., Pauley A.M., Bhattacharya K., Wang Z., Evans D.B., Fleck T.J., Johnston J.A., Sharma S.K. FEBS Lett. 514:263-268(2002) [PubMed: 11943163] [Abstract] Cited for: INTERACTION WITH MAPT, FUNCTION.

9. "APP binds DR6 to trigger axon pruning and neuron death via distinct caspases." Nikolaev A., McLaughlin T., O'Leary D.D.M., Tessier-Lavigne M. Nature 457:981-989(2009) [PubMed: 19225519] [Abstract] Cited for: FUNCTION, CLEAVAGE, INTERACTION WITH TNFRSF21.


10. NCBI Reference Sequence: NP_001155.1

11. http://www.ncbi.nlm.nih.gov/protein/Q9QXJ1.2?ordinalpos=6&itool=EntrezSystem2.PEntrez.Sequence.Sequence_ResultsPanel.Sequence_RVDocSum

12. http://www.ncbi.nlm.nih.gov/protein/Q9QXJ1.2?ordinalpos=6&itool=EntrezSystem2.PEntrez.Sequence.Sequence_ResultsPanel.Sequence_RVDocSum

13. "The intracellular domain of the beta-amyloid precursor protein is stabilized by Fe65 and translocates to the nucleus in a notch-like manner." Kimberly W.T., Zheng J.B., Guenette S.Y., Selkoe D.J. J. Biol. Chem. 276:40288-40292(2001) [PubMed: 11544248] [Abstract] Cited for: INTERACTION WITH APBB1, FUNCTION, SUBCELLULAR LOCATION.

14. Vivian Hook, Israel Schechter, Hans-Ulrich Demuth, Gregory Hook. Alternative Pathways for Production of Beta-Amyloid Peptides of Alzheimer’s Disease.Biol Chem. 2008 August; 389(8): 993–1006. PMCID: PMC2654319

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