p55 protein is a member of PSD scaffold proteins in the rat brain and interacts with various PSD proteins

• Published in: Brain research. Molecular brain research. Vol. 135; no. 1; pp. 204 - 216
• Main Authors: Jing-Ping, Zhang, Tian, Qing-Bao, Sakagami, Hiroyuki, Kondo, Hisatake, Endo, Shogo, Suzuki, Tatsuo
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 27.04.2005; Elsevier
• Subjects: Amino Acid Sequence; Animals; Animals, Newborn; Antibody Specificity; Biological and medical sciences; Blotting, Northern; Blotting, Western - methods; Brain - cytology; Brain - embryology; Brain - metabolism; Calcium-Calmodulin-Dependent Protein Kinases - metabolism; Cells, Cultured; Cloning, Molecular - methods; Disks Large Homolog 4 Protein; DNA, Complementary - metabolism; Electrophoretic Mobility Shift Assay - methods; Embryo, Mammalian; Fluorescent Antibody Technique - methods; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Developmental - physiology; Guanylate Kinases; Immunoprecipitation - methods; In Situ Hybridization - methods; Intracellular Signaling Peptides and Proteins; MAGuK; Male; Membrane Proteins; Multiprotein Complexes - metabolism; Nerve Tissue Proteins - classification; Nerve Tissue Proteins - genetics; Nerve Tissue Proteins - immunology; Nerve Tissue Proteins - metabolism; Neurons - metabolism; p55; Postsynaptic density; Protein Structure, Tertiary - physiology; Protein–protein interaction; Rats; Rats, Wistar; Reverse Transcriptase Polymerase Chain Reaction - methods; RNA, Messenger - biosynthesis; Scaffold; Signal Transduction; Subcellular Fractions - metabolism; Synapse; Synaptophysin - metabolism; Time Factors; Vertebrates: nervous system and sense organs; PSD; Excitable membranes and synaptic transmission; ORF; GK; GST; r-p55; Scaffold; MPP; Dem; Protein–protein interaction; SPM; p55; MAGuK; Synapse; CaMKII; RT-PCR; Postsynaptic density; VAM-1; PCR; Rat; Protein-protein interaction; Rodentia; Central nervous system; Protein; Encephalon; Vertebrata; Mammalia; Animal
• ISSN: 0169-328X; 1872-6941
• DOI: 10.1016/j.molbrainres.2004.12.023

p55 is a membrane-associated guanylate kinase (MAGuK) family member that consists of a single PDZ followed by SH3, HOOK and guanylate kinase (GuK or GK) domains. We investigated rat p55 (r-p55) in the brain. r-p55 mRNA was expressed widely in various tissues and in various regions of the brain. r-p55 protein was also expressed widely in various rat tissues, including brain and erythrocytes. The protein was enriched in the synaptic plasma membrane and postsynaptic density (PSD) fractions of the forebrain. An immunocytochemical study using cultured cortical neurons suggested postsynaptic localization of r-p55 protein. Pull-down assay showed that r-p55 protein interacted with r-p55 itself and various PSD proteins, such as PSD-95, SAP97, GKAP, CASK, GRIP, neuroligin, cadherin, tubulin, actin, α-internexin, neurofilament-L and Ca 2+/calmodulin-dependent protein kinase II, through its PDZ, SH3, HOOK or GK domains. The interaction with PSD-95 was found to occur between the PDZ domains of PSD-95 and the HOOK and GK domains of r-p55 protein. These findings, together with the presence of r-p55 puncta in a period of early synaptogenesis, suggest that r-p55 protein functions as one of postsynaptic scaffold component in an early stage of synaptogenesis in the brain. r-p55 protein may form a basic structure, which interlinks diverse functional molecules of the PSD necessary for postsynaptic signaling and synaptic adhesion.