Biomedical subjects

Akira Kawata

Publications and source records attributed to Akira Kawata.

3 recordsLinked to original sources

PubMed2006

Synaptic scaffolding molecule (S-SCAM) membrane-associated guanylate kinase with inverted organization (MAGI)-2 is associated with cell adhesion molecules at inhibitory synapses in rat hippocampal neurons.

Synaptic scaffolding molecule (S-SCAM) is a synaptic protein, which harbors five or six PSD-95/Discs large/ZO-1 (PDZ), a guanylate kinase and two WW domains. It interacts with NMDA receptor subunits, neuroligin and beta-catenin, and is involved in the accumulation of neuroligin at excitatory synapses. In this study, we have demonstrated S-SCAM is localized at inhibitory synapses in rat primary cultured hippocampal neurons. We have identified beta-dystroglycan (beta-DG) as a binding partner for S-SCAM at inhibitory synapses. WW domains of S-SCAM bind to three sequences of beta-DG. We have also revealed that S-SCAM can interact with neuroligin 2, which is known to be exclusively localized at inhibitory synapses. The WW domains and the second PDZ domain of S-SCAM are involved in the interaction with neuroligin 2. Beta-DG, neuroligin 2 and S-SCAM form a tripartite complex in vitro. Neuroligin 2 is detected in the immunoprecipitates by anti-beta-DG antibody from rat brain. S-SCAM, beta-DG and neuroligin 2 are partially co-localized in rat hippocampal neurons. These data suggest that S-SCAM is associated with beta-DG and neuroligin 2 at inhibitory synapses, and functions as a linker between the dystrophin glycoprotein complex and the neurexin-neuroligin complex.

Adaptor Proteins, Signal Transducing↗

PubMed2006

CIN85 is localized at synapses and forms a complex with S-SCAM via dendrin.

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.

Adaptor Proteins, Signal Transducing↗

PubMed2003

Surgical approach to tumor recurrence and metastatic lesions of the liver in a patient with malignant endocrine tumors of the pancreas: case report.

We describe herein a 72-year-old woman with tumor recurrence in the residual pancreas and metastasis to the liver following a pylorus-preserving pancreatoduodenectomy for multiple endocrine tumors in the head of the pancreas. Abdominal ultrasonography performed 7 years after the initial surgery detected new lesions in the residual pancreas and liver. After recurrence of endocrine tumors of the pancreas and metastasis to the liver were diagnosed, the lesions were successfully resected by total pancreatectomy with distal gastrectomy and both lateral segmentectomy and partial resection of segment 8. Genetic analysis using a blood specimen showed that this patient carried the multiple endocrine neoplasia type 1 (MEN1) gene mutation. One year after the second resection, the patient remains in good health using insulin and has not shown any sign of recurrence. This case report describes successful surgical resection for recurrence and metastasis of malignant endocrine tumors in a patient with the MEN1 gene mutation.

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