PSD-95 Interacts with NBCn1 and Enhances Channel-like Activity without Affecting Na/HCO3Cotransport
| Autor: | C. Chris Yun, Soojung Lee, Yoland Smith, Han Soo Yang, R. Kyle Dudley, Eun Ji Ju, Inyeong Choi, Min Hyung Kwon, Eunjin Kim |
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| Rok vydání: | 2012 |
| Předmět: |
Physiology
Dendritic Spines Xenopus Intracellular pH PDZ Domains Bicarbonate transporter protein Biology Binding Competitive Article Rats Sprague-Dawley Postsynaptic potential Animals Humans chemistry.chemical_classification Sodium-Bicarbonate Symporters HEK 293 cells Intracellular Signaling Peptides and Proteins Membrane Proteins Bicarbonate transport Hydrogen-Ion Concentration CA3 Region Hippocampal Peptide Fragments Rats Amino acid HEK293 Cells Sodium Bicarbonate nervous system Biochemistry chemistry Synapses Biophysics Cotransporter Disks Large Homolog 4 Protein Postsynaptic density Protein Binding |
| Zdroj: | Cellular Physiology and Biochemistry. 30:1444-1455 |
| ISSN: | 1421-9778 1015-8987 |
| Popis: | Background/Aims: The sodium/bicarbonate transporter NBCn1 plays an essential role in intracellular pH regulation and transepithelial HCO3– movement in the body. NBCn1 also has sodium channel-like activity uncoupled to Na/HCO3 cotransport. We previously reported that NBCn1 interacts with the postsynaptic density protein PSD-95 in the brain. Here, we elucidated the structural determinant and functional consequence of NBCn1/PSD-95 interaction. Methods: Results: In rat hippocampal CA3 neurons, NBCn1 was localized to the postsynaptic membranes of both dendritic shafts and spines and occasionally to the presynaptic membranes. A GST/NBCn1 fusion protein containing the C-terminal 131 amino acids of NBCn1 pulled down PSD-95 from rat brain lysates, whereas GST/NBCn1-ΔETSL (deletion of the last four amino acids) and GST/NBCn2 (NCBE) lacking the same ETSL did not. NBCn1 and PSD-95 were coimmunoprecipitated in HEK 293 cells, and their interaction did not affect the efficacy of PSD-95 to bind to the NMDA receptor NR2A. PSD-95 has negligible effects on intracellular pH changes mediated by NBCn1 in HEK 293 cells and Xenopus oocytes. However, PSD-95 increased an ionic conductance produced by NBCn1 channel-like activity. This increase was abolished by NBCn1-ΔETSL or by the peptide containing the last 15 amino acids of NBCn1. Conclusion: Our data suggest that PSD-95 interacts with NBCn1 and increases its channel-like activity while negligibly affecting Na/HCO3 cotransport. The possibility that the channel-like activity occurs via an intermolecular cavity of multimeric NBCn1 proteins is discussed. |
| Databáze: | OpenAIRE |
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