Laboratory of Neurobiology, Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 842 51 Bratislava, Slovakia.
Neurochem Int. 2010 Oct;57(3):254-61. doi: 10.1016/j.neuint.2010.06.003. Epub 2010 Jun 11.
Glycine transporter GlyT1 plays important role in maintaining accurate glycine concentration in local brain microenvironment. Transporting efficiency of GlyT1 is strongly affected by the state of its distal C-terminus, which regulates transporter trafficking and cellular surface density. Using selected range of antibody epitopes against C-terminal region of GlyT1 we investigated its changes during calcium overload, the ubiquitous phenomena of several brain pathologies. We show that immunoreactivity against the last 12 amino acids of GlyT1C-terminal region exhibits robust calcium dependent decline, while the immunoreactivity of closely located region shows relatively small changes. Process is fully blocked by calcium chelation and inhibited by cysteine proteases inhibitors as well as inhibitors of protein kinase C. Distal GlyT1C-terminal end contains PDZ binding motif responsible for GlyT1 interaction with trafficking and clustering proteins. Its removal/modification could be part of the mechanism changing glycine homeostasis during physiological/pathological conditions characterized by elevated calcium.
甘氨酸转运体 GlyT1 在维持局部脑微环境中甘氨酸浓度的准确性方面发挥着重要作用。GlyT1 的转运效率受到其远端 C 末端状态的强烈影响,C 末端调节着转运体的运输和细胞表面密度。我们使用针对 GlyT1 C 末端区域的一系列选定抗体表位来研究其在钙超载期间的变化,钙超载是几种脑病理学的普遍现象。我们发现,针对 GlyT1 C 末端最后 12 个氨基酸的免疫反应表现出强烈的钙依赖性下降,而靠近的区域的免疫反应则变化相对较小。该过程完全被钙螯合剂阻断,并被半胱氨酸蛋白酶抑制剂以及蛋白激酶 C 抑制剂抑制。远端 GlyT1 C 末端包含 PDZ 结合基序,负责 GlyT1 与运输和聚类蛋白的相互作用。其缺失/修饰可能是在生理/病理条件下改变甘氨酸动态平衡的机制的一部分,这些条件的特征是钙升高。