Inosine monophosphate dehydrogenase (IMPDH) is a rate-limiting enzyme in the de novo GTP biosynthesis pathway. Recent studies suggest that IMPDH2, an isoform of IMPDH, can localize to specific subcellular compartments under certain conditions and regulate site-specific GTP availability and small GTPase activity in invasive cancer cells. However, it is unclear whether IMPDH2 plays a site-specific regulatory role in subcellular functions in healthy cells. In this study, we focused on brain cells and examined the localization pattern of IMPDH2. We discovered that IMPDH2 forms localized spots in the astrocytes of the adult mouse hippocampus. Further analysis of spot distribution in primary astrocyte cultures revealed that IMPDH2 spots are predominantly localized on branching sites and distal ends of astrocyte stem processes. Our findings suggest a potential unidentified role for IMPDH2 and GTP synthesis specifically at specialized nodes of astrocyte branches.

中文翻译：

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IMPDH2 在星形胶质细胞干突的分支部位和远端形成斑点

肌苷单磷酸脱氢酶 (IMPDH) 是 GTP 从头生物合成途径中的限速酶。最近的研究表明，IMPDH2（IMPDH 的一种亚型）在某些条件下可以定位到特定的亚细胞区室，并调节侵袭性癌细胞中特定位点的 GTP 可用性和小 GTP 酶活性。然而，尚不清楚IMPDH2是否在健康细胞的亚细胞功能中发挥位点特异性调节作用。在这项研究中，我们关注脑细胞并检查 IMPDH2 的定位模式。我们发现 IMPDH2 在成年小鼠海马体的星形胶质细胞中形成局部斑点。对原代星形胶质细胞培养物中斑点分布的进一步分析表明，IMPDH2 斑点主要位于星形胶质细胞干突的分支位点和远端。我们的研究结果表明，IMPDH2 和 GTP 合成的潜在作用尚未确定，特别是在星形胶质细胞分支的特殊节点上。