title: POF1B localizes to desmosomes and regulates cell adhesion in human intestinal and keratinocyte cell lines.
abstract: By means of morphological and biochemical criteria, we here provide evidence for the localization and function of premature ovarian failure, 1B (POF1B) in desmosomes. In monolayers of Caco-2 intestinal cells and in stratified HaCaT keratinocytes, endogenous POF1B colocalized with desmoplakin at desmosome plaques and in cytoplasmic particles aligned along intermediate filaments (IFs). POF1B predominantly co-fractionated with desmosomes and IF components and exhibited properties characteristic of desmosomes (i.e., detergent insolubility and calcium independence). The role of NH2 and COOH domains in the association of POF1B with desmosomes and IFs was revealed by transient expression of the truncated protein in Caco-2 cells and in cells lacking desmosomes. The function of POF1B in desmosomes was investigated in HaCaT keratinocytes stably downregulated for POF1B expression. Transmission electron microscopy analysis revealed a decrease in desmosome number and size, and desmosomes of the downregulated keratinocytes displayed weak electron-dense plaques. Desmosome alterations were associated with defects in cell adhesion, as revealed by the reduced resistance to mechanical stress in the dispase fragmentation assay. Moreover, desmosome localization of POF1B was restricted to granular layers in human healthy epidermis, whereas it largely increased in hyperproliferative human skin diseases, thus demonstrating the localization of POF1B also in desmosomes of multistratified epithelia.
authors.affiliation: Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano and CNR Institute of Neuroscience, Milan, Italy.
authors.forename: Arianna
authors.initials: A
authors.lastname: Crespi
authors.affiliation: Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano and CNR Institute of Neuroscience, Milan, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Bertoni
authors.affiliation: Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano and CNR Institute of Neuroscience, Milan, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Ferrari
authors.affiliation: Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano and CNR Institute of Neuroscience, Milan, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Padovano
authors.affiliation: Consorzio MIA and DISS, Università Milano-Bicocca, Milan, Italy.
authors.forename: Pamela
authors.initials: P
authors.lastname: Della Mina
authors.affiliation: Consorzio MIA and DISS, Università Milano-Bicocca, Milan, Italy; Department of Dermatology, Fondazione Ca `Granda, Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: Emilio
authors.initials: E
authors.lastname: Berti
authors.affiliation: Consorzio MIA and DISS, Università Milano-Bicocca, Milan, Italy.
authors.forename: Antonello
authors.initials: A
authors.lastname: Villa
authors.affiliation: Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano and CNR Institute of Neuroscience, Milan, Italy. Electronic address: grazia.pietrini@unimi.it.
authors.forename: Grazia
authors.initials: G
authors.lastname: Pietrini
mesh_terms: D018938:Caco-2 Cells; D002118:Calcium / Q000378:metabolism; D002448:Cell Adhesion / Q000502:physiology; D049109:Cell Proliferation; D003593:Cytoplasm / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D051180:Desmoplakins / Q000378:metabolism; D003896:Desmosomes / Q000378:metabolism* / Q000648:ultrastructure; D000078404:Epidermal Cells; D004817:Epidermis / Q000378:metabolism; D005260:Female; D006801:Humans; D007422:Intestines / Q000166:cytology; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism*; D008840:Microfilament Proteins; D046529:Microscopy, Electron, Transmission; D016649:Primary Ovarian Insufficiency / Q000378:metabolism* / Q000473:pathology; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012871:Skin Diseases / Q000378:metabolism* / Q000473:pathology; D013314:Stress, Mechanical
chemical_list: D018076:DNA, Complementary; C495294:DSP protein, human; D051180:Desmoplakins; D008840:Microfilament Proteins; C500687:POF1B protein, human; D011506:Proteins; D002118:Calcium