title: Endogenous interleukin 1 alpha must be transported to the nucleus to exert its activity in human endothelial cells.
abstract: We have previously shown that the signal peptideless cytokine interleukin 1 alpha (IL-1 alpha) may play a role as an intracellular regulator of human endothelial cell senescence (J. A. M. Maier, P. Voulalas, D. Roeder, and T. Maciag, Science 249:1570-1574, 1990). To investigate the potential intracellular function of IL-1 alpha, transformed endothelial cells were transfected with the human cDNAs that code for the two forms of IL-1 alpha, the precursor molecule IL-1(1-271) and the mature protein IL-1(113-271). The subcellular localization of the two different polypeptides was investigated directly or by using chimeric genes constructed by fusion of different fragments of the IL-1 alpha gene and the beta-galactosidase open reading frames. The IL-1(113-271) protein was cytoplasmic, while IL-1(1-271) was nuclear. The basic cluster at the NH2 terminus of IL-1, KVLKKRR, has been shown to mediate IL-1 alpha nuclear targeting. Moreover, nuclear localization of IL-1 alpha correlates with impaired cell growth and expression of some IL-1 alpha-inducible genes. These results suggest that transport of endogenous IL-1(1-271) into the nucleus is required for it to modulate endothelial cell function.
authors.affiliation: Department of Biomedical Science, University of Milan School of Medicine, Italy.
authors.forename: J A
authors.initials: JA
authors.lastname: Maier
authors.forename: M
authors.initials: M
authors.lastname: Statuto
authors.forename: G
authors.initials: G
authors.lastname: Ragnotti
mesh_terms: D001483:Base Sequence; D001692:Biological Transport; D002451:Cell Compartmentation; D002455:Cell Division; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D017364:Collagenases / Q000235:genetics; D017931:DNA Primers / Q000737:chemistry; D004730:Endothelium, Vascular / Q000502:physiology*; D005455:Fluorescent Antibody Technique; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D066298:In Vitro Techniques; D007375:Interleukin-1 / Q000378:metabolism* / Q000502:physiology; D008969:Molecular Sequence Data; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D011994:Recombinant Proteins; D014162:Transfection
chemical_list: D017931:DNA Primers; D007375:Interleukin-1; D017395:Plasminogen Activator Inhibitor 1; D012333:RNA, Messenger; D011994:Recombinant Proteins; D017364:Collagenases