title: P-glycoprotein-actin association through ERM family proteins: a role in P-glycoprotein function in human cells of lymphoid origin.
abstract: P-glycoprotein is a 170-kd glycosylated transmembrane protein, expressed in a variety of human cells and belonging to the adenosine triphosphate-binding cassette transporter family, whose membrane expression is functionally associated with the multidrug resistance phenotype. However, the mechanisms underlying the regulation of P-glycoprotein functions remain unclear. On the basis of some evidence suggesting P-glycoprotein-actin cytoskeleton interaction, this study investigated the association of P-glycoprotein with ezrin, radixin, and moesin, a class of proteins that cross-link actin filaments with plasma membrane in a human cell line of lymphoid origin and that have been shown to link other ion-pump-related proteins. To this purpose, a multidrug-resistant variant of CCRF-CEM cells (CEM-VBL100) was used as a model to investigate the following: (1) the cellular localizations of P-glycoprotein and ezrin, radixin, and moesin and their molecular associations; and (2) the effects of ezrin, radixin, and moesin antisense oligonucleotides on multidrug resistance and P-glycoprotein function. The results showed that: (1) P-glycoprotein colocalized and coimmunoprecipitated with ezrin, radixin, and moesin; and (2) treatment with antisense oligonucleotides for ezrin, radixin, and moesin restored drug susceptibility consistently with inhibition of both drug efflux and actin-P-glycoprotein association and induction of cellular redistribution of P-glycoprotein. These data suggest that P-glycoprotein association with the actin cytoskeleton through ezrin, radixin, and moesin is key in conferring to human lymphoid cells a multidrug resistance phenotype. Strategies aimed at inhibiting P-glycoprotein-actin association may be helpful in increasing the efficiency of both antitumor and antiviral therapies.
authors.affiliation: Laboratory of Immunology and Ultrastructures, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Luciani
authors.forename: Agnese
authors.initials: A
authors.lastname: Molinari
authors.forename: Francesco
authors.initials: F
authors.lastname: Lozupone
authors.forename: Annarica
authors.initials: A
authors.lastname: Calcabrini
authors.forename: Luana
authors.initials: L
authors.lastname: Lugini
authors.forename: Annarita
authors.initials: A
authors.lastname: Stringaro
authors.forename: Patrizia
authors.initials: P
authors.lastname: Puddu
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Arancia
authors.forename: Maurizio
authors.initials: M
authors.lastname: Cianfriglia
authors.forename: Stefano
authors.initials: S
authors.lastname: Fais
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D008841:Actin Cytoskeleton / Q000378:metabolism / Q000648:ultrastructure; D000199:Actins / Q000378:metabolism*; D001798:Blood Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism; D018432:Drug Resistance, Multiple; D006801:Humans; D008214:Lymphocytes / Q000378:metabolism*; D016399:Lymphoma, T-Cell / Q000473:pathology; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism*; D018613:Microscopy, Confocal; D005810:Multigene Family; D020319:Oligodeoxyribonucleotides, Antisense / Q000494:pharmacology; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D011233:Precipitin Tests; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000473:pathology; D013873:Thionucleotides / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D000099149:Ezrin
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000199:Actins; D001798:Blood Proteins; D003598:Cytoskeletal Proteins; D046911:Macromolecular Substances; D008565:Membrane Proteins; D008840:Microfilament Proteins; D020319:Oligodeoxyribonucleotides, Antisense; D010750:Phosphoproteins; D013873:Thionucleotides; D000099149:Ezrin; C071058:moesin; C071776:radixin