Succoio Mariangela, Amiranda Sara, Sasso Emanuele, Marciano Carmen, Finizio Arianna, De Simone Giuseppina, Garbi Corrado, Zambrano Nicola
Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, Via S. Pansini, 5 80131, Napoli, Italy.
CEINGE Biotecnologie avanzate Franco Salvatore SCaRL, Via G. Salvatore, 486 80145, Napoli, Italy.
Heliyon. 2023 Aug 2;9(8):e18885. doi: 10.1016/j.heliyon.2023.e18885. eCollection 2023 Aug.
The human carbonic anhydrase IX (CA IX) is a hypoxia-induced transmembrane protein belonging to the α-CA enzyme family. It has a crucial role in pH regulation in hypoxic cells and acts by buffering intracellular acidosis induced by hypoxia. Indeed, it is frequently expressed in cancer cells, where it contributes to tumor progression. CA IX is also able to localize in the nucleus, where it contributes to 47S rRNA precursor genes transcription; however, the mechanisms assisting its nuclear translocation still remain unclear. The aim of our study was to deepen the understanding of the mechanisms involved in CA IX subcellular distribution. To this purpose, we implemented a site-directed mutagenesis approach targeting the C-terminal domain of CA IX and evaluated the subcellular distribution of the wild-type and mutant proteins in the SH-SY5Y cell line. The mutant proteins showed impaired binding ability and altered subcellular distribution in both normoxic and hypoxic conditions. Our data suggest that CA IX nuclear translocation depends on its transit through the secretory and the endocytic pathways.
人类碳酸酐酶IX（CA IX）是一种由缺氧诱导的跨膜蛋白，属于α-碳酸酐酶家族。它在缺氧细胞的pH调节中起关键作用，通过缓冲缺氧诱导的细胞内酸中毒发挥作用。实际上，它在癌细胞中经常表达，对肿瘤进展有促进作用。CA IX也能够定位于细胞核，在那里它有助于47S rRNA前体基因的转录；然而，协助其核转位的机制仍不清楚。我们研究的目的是加深对CA IX亚细胞分布所涉及机制的理解。为此，我们实施了一种针对CA IX C末端结构域的定点诱变方法，并评估了野生型和突变型蛋白在SH-SY5Y细胞系中的亚细胞分布。突变型蛋白在常氧和缺氧条件下均表现出结合能力受损和亚细胞分布改变。我们的数据表明，CA IX的核转位取决于其通过分泌途径和内吞途径的转运。
