title: Transmembrane protein PERP is a component of tessellate junctions and of other junctional and non-junctional plasma membrane regions in diverse epithelial and epithelium-derived cells.
abstract: Protein PERP (p53 apoptosis effector related to PMP-22) is a small (21.4 kDa) transmembrane polypeptide with an amino acid sequence indicative of a tetraspanin character. It is enriched in the plasma membrane and apparently contributes to cell-cell contacts. Hitherto, it has been reported to be exclusively a component of desmosomes of some stratified epithelia. However, by using a series of newly generated mono- and polyclonal antibodies, we show that protein PERP is not only present in all kinds of stratified epithelia but also occurs in simple, columnar, complex and transitional epithelia, in various types of squamous metaplasia and epithelium-derived tumors, in diverse epithelium-derived cell cultures and in myocardial tissue. Immunofluorescence and immunoelectron microscopy allow us to localize PERP predominantly in small intradesmosomal locations and in variously sized, junction-like peri- and interdesmosomal regions ("tessellate junctions"), mostly in mosaic or amalgamated combinations with other molecules believed, to date, to be exclusive components of tight and adherens junctions. In the heart, PERP is a major component of the composite junctions of the intercalated disks connecting cardiomyocytes. Finally, protein PERP is a cobblestone-like general component of special plasma membrane regions such as the bile canaliculi of liver and subapical-to-lateral zones of diverse columnar epithelia and upper urothelial cell layers. We discuss possible organizational and architectonic functions of protein PERP and its potential value as an immunohistochemical diagnostic marker.
authors.affiliation: German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany. w.franke@dkfz.de
authors.forename: Werner W
authors.initials: WW
authors.lastname: Franke
authors.forename: Hans
authors.initials: H
authors.lastname: Heid
authors.forename: Ralf
authors.initials: R
authors.lastname: Zimbelmann
authors.forename: Caecilia
authors.initials: C
authors.lastname: Kuhn
authors.forename: Stefanie
authors.initials: S
authors.lastname: Winter-Simanowski
authors.forename: Yvette
authors.initials: Y
authors.lastname: Dörflinger
authors.forename: Christine
authors.initials: C
authors.lastname: Grund
authors.forename: Steffen
authors.initials: S
authors.lastname: Rickelt
mesh_terms: D016475:3T3 Cells; D022005:Adherens Junctions / Q000378:metabolism*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D002417:Cattle; D045744:Cell Line, Tumor; D002462:Cell Membrane; D003896:Desmosomes / Q000378:metabolism; D004847:Epithelial Cells; D004848:Epithelium / Q000378:metabolism*; D016147:Genes, Tumor Suppressor; D019073:HT29 Cells; D056945:Hep G2 Cells; D006801:Humans; D061986:MCF-7 Cells; D008565:Membrane Proteins / Q000032:analysis / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D051381:Rats; D013552:Swine
chemical_list: D000911:Antibodies, Monoclonal; D008565:Membrane Proteins; C416404:PERP protein, human