Molecular and Cell Biology, Department of Biosciences (FR 8.3) and Center of Human and Molecular Biology (ZHMB), Saarland University, D-66123, Saarbrücken, Germany.
Cluster of Excellence, Multimodal Computing and Interaction, Saarland University and Department for Computational Biology and Applied Algorithmics, Max Planck Institute for Informatics, Saarland Informatics Campus, Saarbrücken, Germany.
Sci Rep. 2019 Jul 23;9(1):10611. doi: 10.1038/s41598-019-47027-5.
KDEL receptors (KDELRs) represent transmembrane proteins of the secretory pathway which regulate the retention of soluble ER-residents as well as retrograde and anterograde vesicle trafficking. In addition, KDELRs are involved in the regulation of cellular stress response and ECM degradation. For a deeper insight into KDELR1 specific functions, we characterised a KDELR1-KO cell line (HAP1) through whole transcriptome analysis by comparing KDELR1-KO cells with its respective HAP1 wild-type. Our data indicate more than 300 significantly and differentially expressed genes whose gene products are mainly involved in developmental processes such as cell adhesion and ECM composition, pointing out to severe cellular disorders due to a loss of KDELR1. Impaired adhesion capacity of KDELR1-KO cells was further demonstrated through in vitro adhesion assays, while collagen- and/or laminin-coating nearly doubled the adhesion property of KDELR1-KO cells compared to wild-type, confirming a transcriptional adaptation to improve or restore the cellular adhesion capability. Perturbations within the secretory pathway were verified by an increased secretion of ER-resident PDI and decreased cell viability under ER stress conditions, suggesting KDELR1-KO cells to be severely impaired in maintaining cellular homeostasis.
KDEL 受体（KDELRs）是分泌途径中的跨膜蛋白，它们调节可溶性内质网驻留蛋白的保留以及逆行和顺行囊泡运输。此外，KDELRs 还参与细胞应激反应和细胞外基质降解的调节。为了更深入地了解 KDELR1 的特定功能，我们通过比较 KDELR1-KO 细胞与其相应的 HAP1 野生型，通过全转录组分析对 KDELR1-KO 细胞系（HAP1）进行了表征。我们的数据表明，超过 300 个基因的表达显著且差异，其产物主要参与细胞粘附和细胞外基质组成等发育过程，表明由于 KDELR1 的缺失导致严重的细胞紊乱。通过体外粘附实验进一步证明了 KDELR1-KO 细胞的粘附能力受损，而胶原蛋白和/或层粘连蛋白涂层使 KDELR1-KO 细胞的粘附特性比野生型几乎增加了一倍，证实了转录适应性以改善或恢复细胞粘附能力。在分泌途径中出现的紊乱通过内质网驻留蛋白 PDI 的分泌增加和内质网应激条件下细胞活力的降低得到证实，表明 KDELR1-KO 细胞在维持细胞内稳态方面严重受损。
