Yee Sook Wah, Ferrández-Peral Luis, Alentorn Pol, Fontsere Claudia, Ceylan Merve, Koleske Megan L, Handin Niklas, Artegoitia Virginia M, Lara Giovanni, Chien Huan-Chieh, Zhou Xujia, Dainat Jacques, Zalevsky Arthur, Sali Andrej, Brand Colin M, Capra John A, Artursson Per, Newman John W, Marques-Bonet Tomas, Giacomini Kathleen M
Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California, USA.
Institute of Evolutionary Biology (UPF-CSIC), PRBB, 08003 Barcelona, Spain.
bioRxiv. 2023 Aug 12:2023.08.08.552553. doi: 10.1101/2023.08.08.552553.
SLC22A10 is classified as an orphan transporter with unknown substrates and function. Here we describe the discovery of the substrate specificity and functional characteristics of SLC22A10. The human SLC22A10 tagged with green fluorescent protein was found to be absent from the plasma membrane, in contrast to the SLC22A10 orthologs found in great apes. Estradiol-17β-glucuronide accumulated in cells expressing great ape SLC22A10 orthologs (over 4-fold, p<0.001). In contrast, human SLC22A10 displayed no uptake function. Sequence alignments revealed two amino acid differences including a proline at position 220 of the human SLC22A10 and a leucine at the same position of great ape orthologs. Site-directed mutagenesis yielding the human SLC22A10-P220L produced a protein with excellent plasma membrane localization and associated uptake function. Neanderthal and Denisovan genomes show human-like sequences at proline 220 position, corroborating that SLC22A10 were rendered nonfunctional during hominin evolution after the divergence from the pan lineage (chimpanzees and bonobos). These findings demonstrate that human SLC22A10 is a unitary pseudogene and was inactivated by a missense mutation that is fixed in humans, whereas orthologs in great apes transport sex steroid conjugates.
溶质载体家族22成员10（SLC22A10）被归类为一种底物和功能未知的孤儿转运蛋白。在此，我们描述了SLC22A10底物特异性和功能特性的发现。与在大猩猩中发现的SLC22A10直系同源物相比，发现绿色荧光蛋白标记的人类SLC22A10不在质膜上。17β-葡萄糖醛酸雌二醇在表达大猩猩SLC22A10直系同源物的细胞中积累（超过4倍，p<0.001）。相比之下，人类SLC22A10没有摄取功能。序列比对揭示了两个氨基酸差异，包括人类SLC22A10第220位的脯氨酸和大猩猩直系同源物相同位置的亮氨酸。定点诱变产生的人类SLC22A10-P220L产生了一种具有优异质膜定位和相关摄取功能的蛋白质。尼安德特人和丹尼索瓦人的基因组在脯氨酸220位置显示出类似人类的序列，证实了SLC22A10在与泛谱系（黑猩猩和倭黑猩猩）分化后的人类进化过程中失去了功能。这些发现表明，人类SLC22A10是一个单一的假基因，因一个在人类中固定的错义突变而失活，而大猩猩中的直系同源物则转运性类固醇结合物。
