title: Nuclear translocation of the 1,25D3-MARRS (membrane associated rapid response to steroids) receptor protein and NFkappaB in differentiating NB4 leukemia cells.
abstract: 1,25 Dihydroxyvitamin D(3) (1,25D(3)) primes NB4 promyelocytic leukemia cells to differentiate along the monocyte/macrophage lineage through a non-genomic mechanism. Here we show that NB4 cells express high levels of the recently identified membrane receptor for 1,25D(3), which is a distinct gene product from the classical nuclear vitamin D receptor. This 57 kDa protein, named 1,25D(3)-MARRS (Membrane Activated Rapid Response to Steroids)/ERp57/PIA3 appears to associate in a complex with the transcription factor, nuclear factor kappa B (NFkappaB). In unstimulated cells, 1,25D(3)-MARRS can be co-immunoprecipitated with antibodies directed at NFkappaB, and NFkappaB is co-precipitated when antibodies against 1,25D(3)-MARRS or ERp57 are used. Confocal microscopy and subcellular fractionation studies demonstrate that both 1,25D(3)-MARRS and NFkappaB begin translocating to the nucleus within minutes of co-stimulation with 1,25D(3) and phorbol ester. The predominant nuclear localization of both proteins precedes the expression of the monocyte/macrophage phenotype and suggests that this event may be critical to the differentiation pathway. This suggests a role for 1,25D(3)-MARRS in the nucleus as a regulator of gene expression. Here it may also regulate the activity of NFkappaB and other factors with which it may be interacting.
authors.affiliation: Department of Human Health, University of Guelph, Guelph, Ontario, Canada.
authors.forename: Wenqing
authors.initials: W
authors.lastname: Wu
authors.forename: Greg
authors.initials: G
authors.lastname: Beilhartz
authors.forename: Yvette
authors.initials: Y
authors.lastname: Roy
authors.forename: Cynthia L
authors.initials: CL
authors.lastname: Richard
authors.forename: Maureen
authors.initials: M
authors.lastname: Curtin
authors.forename: Lauren
authors.initials: L
authors.lastname: Brown
authors.forename: Danielle
authors.initials: D
authors.lastname: Cadieux
authors.forename: Marc
authors.initials: M
authors.lastname: Coppolino
authors.forename: Mary C
authors.initials: MC
authors.lastname: Farach-Carson
authors.forename: Ilka
authors.initials: I
authors.lastname: Nemere
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Meckling
mesh_terms: D021581:Active Transport, Cell Nucleus; D002117:Calcitriol / Q000378:metabolism; D002454:Cell Differentiation; D002458:Cell Fractionation; D002467:Cell Nucleus / Q000378:metabolism*; D015973:Gene Expression Regulation, Leukemic; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D008565:Membrane Proteins / Q000378:metabolism; D018613:Microscopy, Confocal; D016328:NF-kappa B / Q000378:metabolism*; D019704:Protein Disulfide-Isomerases / Q000378:metabolism*; D021381:Protein Transport; D014018:Tissue Distribution; D014407:Tumor Cells, Cultured
chemical_list: D008565:Membrane Proteins; D016328:NF-kappa B; D019704:Protein Disulfide-Isomerases; C085868:PDIA3 protein, human; D002117:Calcitriol