title: CIN85 is localized at synapses and forms a complex with S-SCAM via dendrin.
abstract: Membrane-associated guanylate kinase inverted (MAGI)-1 plays a role as a scaffold at cell junctions in non-neuronal cells, while S-SCAM, its neuronal isoform, is involved in the organization of synapses. A search for MAGI-1-interacting proteins by yeast two-hybrid screening of a kidney cDNA library yielded dendrin. As dendrin was originally reported as a brain-specific postsynaptic protein, we tested the interaction between dendrin and S-SCAM and revealed that dendrin binds to the WW domains of S-SCAM. Dendrin is known to be dendritically translated but its function is largely unknown. To gain insights into the physiological meaning of the interaction, we performed a second yeast two-hybrid screening using dendrin as a bait. We identified CIN85, an endocytic scaffold protein, as a putative dendrin-interactor. Immunocytochemistry and subcellular fractionation analysis supported the synaptic localization of CIN85. The first SH3 domain and the C-terminal region of CIN85 bind to the proline-rich region and the N-terminal region of dendrin, respectively. In vitro experiments suggest that dendrin forms a ternary complex with CIN85 and S-SCAM and that this complex formation facilitates the recruitment of dendrin and S-SCAM to vesicle-like structures where CIN85 is accumulated.
authors.affiliation: Department of Medical Biochemistry, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo 113-8519.
authors.forename: Akira
authors.initials: A
authors.lastname: Kawata
authors.forename: Junko
authors.initials: J
authors.lastname: Iida
authors.forename: Mitsunobu
authors.initials: M
authors.lastname: Ikeda
authors.forename: Yuji
authors.initials: Y
authors.lastname: Sato
authors.forename: Hiroki
authors.initials: H
authors.lastname: Mori
authors.forename: Ai
authors.initials: A
authors.lastname: Kansaku
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Sumita
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Fujiwara
authors.forename: Chiaki
authors.initials: C
authors.lastname: Rokukawa
authors.forename: Mamiko
authors.initials: M
authors.lastname: Hamano
authors.forename: Susumu
authors.initials: S
authors.lastname: Hirabayashi
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Hata
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D020816:Amino Acid Motifs / Q000502:physiology*; D000818:Animals; D001921:Brain / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D051528:Guanylate Kinases / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry / Q000378:metabolism; D007668:Kidney / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000235:genetics / Q000502:physiology; D051381:Rats; D015398:Signal Transduction / Q000502:physiology*; D013569:Synapses / Q000378:metabolism*; D014018:Tissue Distribution; D020798:Two-Hybrid System Techniques
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; C114103:Magi2 protein, rat; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C433810:SH3KBP1 protein, human; C104328:dendrin; D051528:Guanylate Kinases; C508141:Magi1 protein, rat