title: Interaction of reelin with amyloid precursor protein promotes neurite outgrowth.
abstract: The processing of amyloid precursor protein (APP) to Abeta is an important event in the pathogenesis of Alzheimer's disease, but the physiological function of APP is not well understood. Our previous work has shown that APP processing and Abeta production are regulated by the extracellular matrix protein Reelin. In the present study, we examined whether Reelin interacts with APP, and the functional consequences of that interaction in vitro. Using coimmunoprecipitation, we found that Reelin interacted with APP through the central domain of Reelin (repeats 3-6) and the E1 extracellular domain of APP. Reelin increased cell surface levels of APP and decreased endocytosis of APP in hippocampal neurons in vitro. In vivo, Reelin levels were increased in brains of APP knock-out mice and decreased in APP-overexpressing mice. RNA interference knockdown of APP decreased neurite outgrowth in vitro and prevented Reelin from increasing neurite outgrowth. Knock-out of APP or Reelin decreased dendritic arborization in cortical neurons in vivo, and APP overexpression increased dendritic arborization. APP and Reelin have previously been shown to promote neurite outgrowth through interactions with integrins. We confirmed that APP interacted with alpha3beta1 integrin, and alpha3beta1 integrin altered APP trafficking and processing. Addition of an alpha3beta1 integrin antibody prevented APP and Reelin-induced neurite outgrowth. These findings demonstrate that Reelin interacts with APP, potentially having important effects on neurite development.
authors.affiliation: Department of Neuroscience, Georgetown University Medical Center, Washington, DC 20057-1464, USA.
authors.forename: Hyang-Sook
authors.initials: HS
authors.lastname: Hoe
authors.forename: Kea Joo
authors.initials: KJ
authors.lastname: Lee
authors.forename: Rosalind S E
authors.initials: RS
authors.lastname: Carney
authors.forename: Jiyeon
authors.initials: J
authors.lastname: Lee
authors.forename: Alexandra
authors.initials: A
authors.lastname: Markova
authors.forename: Ji-Yun
authors.initials: JY
authors.lastname: Lee
authors.forename: Brian W
authors.initials: BW
authors.lastname: Howell
authors.forename: Bradley T
authors.initials: BT
authors.lastname: Hyman
authors.forename: Daniel T S
authors.initials: DT
authors.lastname: Pak
authors.forename: Guojun
authors.initials: G
authors.lastname: Bu
authors.forename: G William
authors.initials: GW
authors.lastname: Rebeck
mesh_terms: D016564:Amyloid beta-Protein Precursor / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000502:physiology*; D019556:COS Cells; D015816:Cell Adhesion Molecules, Neuronal / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D003712:Dendrites / Q000502:physiology; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D039201:Integrin alpha3beta1 / Q000378:metabolism; D019012:Integrin beta1 / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008818:Mice, Neurologic Mutants; D008822:Mice, Transgenic; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D016501:Neurites / Q000502:physiology*; D058255:Protease Nexins; D051381:Rats; D017207:Rats, Sprague-Dawley; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D000091042:Reelin Protein; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*
chemical_list: C545487:APP protein, human; D016564:Amyloid beta-Protein Precursor; D015816:Cell Adhesion Molecules, Neuronal; D016326:Extracellular Matrix Proteins; D039201:Integrin alpha3beta1; D019012:Integrin beta1; D009419:Nerve Tissue Proteins; D058255:Protease Nexins; D011956:Receptors, Cell Surface; D000091042:Reelin Protein; C000717129:Reln protein, rat; C000717127:RELN protein, human; C000717128:Reln protein, mouse; D012697:Serine Endopeptidases