tailieunhanh - Báo cáo khoa học: MPP3 is recruited to the MPP5 protein scaffold at the retinal outer limiting membrane

Mutations in the human Crumbs homologue 1 (CRB1) gene are a frequent cause of various forms of retinitis pigmentosa. The CRB1–membrane-asso-ciated palmitoylated protein (MPP)5 protein complex is thought to organ-ize an intracellular protein scaffold in the retina that is involved in maintenance of photoreceptor–Mu¨ller glia cell adhesion. | iFEBS Journal MPP3 is recruited to the MPP5 protein scaffold at the retinal outer limiting membrane Albena Kantardzhieva Svetlana Alexeeva Inge Versteeg and Jan Wijnholds Department of NeuromedicalGenetics The Netherlands Institute for Neurosciences NIN KNAW Amsterdam The Netherlands Keywords cell polarity CRB1 DLG1 MPP3 MPP5 Correspondence J. Wijnholds Department of Neuromedical Genetics The Netherlands Institute for Neurosciences NIN Meibergdreef 47 1105 BA Amsterdam the Netherlands Fax 31 20 5666121 Tel 31 20 5664597 E-mail http The authors contributed equally to this work. TPresent address Section Molecular Cytology Swammerdam Institute for Life Sciences University of Amsterdam The Netherlands Database Nucleotide sequence data is available in the DDBJ EMBL GenBank databases under the accession numbers AM050144 AM050145 Received 1 November 2005 revised 11 December 2005 accepted 16 January 2006 doi Mutations in the human Crumbs homologue 1 CRB1 gene are a frequent cause of various forms of retinitis pigmentosa. The CRB1-membrane-asso-ciated palmitoylated protein MPP 5 protein complex is thought to organize an intracellular protein scaffold in the retina that is involved in maintenance of photoreceptor-Muller glia cell adhesion. This study focused on the binding characteristics and subcellular localization of MPP3 a novel member of the MPP5 protein scaffold at the outer limiting membrane OLM and of the DLG1 protein scaffold at the outer plexiform layer of the retina. MPP3 localized at the photoreceptor synapse and at the sub-apical region adjacent to adherens junctions at the OLM. Localization studies in human retinae revealed that MPP3 colocalized with MPP5 and CRB1 at the subapical region. MPP3 and MPP4 colocalized with DLG1 at the outer plexiform layer. Mouse Dlg1 formed separate complexes with Mpp3 and Mpp4 in vivo. These data implicate a role for MPP3 in photoreceptor polarity