Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, New York, United States of America.
Department of Cell Biology & Anatomy, New York Medical College, Valhalla, New York, United States of America.
PLoS One. 2023 Dec 15;18(12):e0295710. doi: 10.1371/journal.pone.0295710. eCollection 2023.
Pannexins are ubiquitously expressed in human and mouse tissues. Pannexin 1 (Panx1), the most thoroughly characterized member of this family, forms plasmalemmal membrane channels permeable to relatively large molecules, such as ATP. Although human and mouse Panx1 amino acid sequences are conserved in the presently known regulatory sites involved in trafficking and modulation of the channel, differences are reported in the N- and C-termini of the protein, and the mechanisms of channel activation by different stimuli remain controversial. Here we used a neuroblastoma cell line to study the activation properties of endogenous mPanx1 and exogenously expressed hPanx1. Dye uptake and electrophysiological recordings revealed that in contrast to mouse Panx1, the human ortholog is insensitive to stimulation with high extracellular [K+] but responds similarly to activation of the purinergic P2X7 receptor. The two most frequent Panx1 polymorphisms found in the human population, Q5H (rs1138800) and E390D (rs74549886), exogenously expressed in Panx1-null N2a cells revealed that regarding P2X7 receptor mediated Panx1 activation, the Q5H mutant is a gain of function whereas the E390D mutant is a loss of function variant. Collectively, we demonstrate differences in the activation between human and mouse Panx1 orthologs and suggest that these differences may have translational implications for studies where Panx1 has been shown to have significant impact.
质膜通道蛋白家族在人体和鼠组织中广泛表达。质膜通道蛋白 1（Panx1）是该家族中研究最透彻的成员，它形成的质膜通道可允许相对较大的分子（如 ATP）通过。尽管人和鼠 Panx1 的氨基酸序列在目前已知的与通道运输和调节相关的调节位点中是保守的，但在蛋白质的 N 端和 C 端仍存在差异，并且不同刺激物激活通道的机制仍存在争议。在这里，我们使用神经母细胞瘤细胞系来研究内源性 mPanx1 和外源性表达的 hPanx1 的激活特性。染料摄取和电生理记录表明，与鼠 Panx1 不同，人源同系物对高细胞外 [K+]刺激不敏感，但对嘌呤能 P2X7 受体的激活反应相似。在人群中发现的两种最常见的 Panx1 多态性，Q5H（rs1138800）和 E390D（rs74549886），在 Panx1 缺失的 N2a 细胞中表达，结果表明，在 P2X7 受体介导的 Panx1 激活方面，Q5H 突变体是功能获得性突变体，而 E390D 突变体是功能丧失性突变体。综上所述，我们证明了人源和鼠源 Panx1 同系物之间的激活存在差异，并表明这些差异可能对 Panx1 具有重要影响的研究具有转化意义。
