Department of Biology, University of Copenhagen, Copenhagen, Denmark.
Department of Human Genetics, Research Institute for Medical Innovation, Radboud University Medical Center, Nijmegen, The Netherlands.
EMBO Rep. 2024 Jul;25(7):3040-3063. doi: 10.1038/s44319-024-00170-1. Epub 2024 Jun 7.
Polarized vesicular trafficking directs specific receptors and ion channels to cilia, but the underlying mechanisms are poorly understood. Here we describe a role for DLG1, a core component of the Scribble polarity complex, in regulating ciliary protein trafficking in kidney epithelial cells. Conditional knockout of Dlg1 in mouse kidney causes ciliary elongation and cystogenesis, and cell-based proximity labeling proteomics and fluorescence microscopy show alterations in the ciliary proteome upon loss of DLG1. Specifically, the retromer-associated protein SDCCAG3, IFT20, and polycystin-2 (PC2) are reduced in the cilia of DLG1-deficient cells compared to control cells. This phenotype is recapitulated in vivo and rescuable by re-expression of wild-type DLG1, but not a Congenital Anomalies of the Kidney and Urinary Tract (CAKUT)-associated DLG1 variant, p.T489R. Finally, biochemical approaches and Alpha Fold modelling suggest that SDCCAG3 and IFT20 form a complex that associates, at least indirectly, with DLG1. Our work identifies a key role for DLG1 in regulating ciliary protein composition and suggests that ciliary dysfunction of the p.T489R DLG1 variant may contribute to CAKUT.
极性囊泡运输将特定的受体和离子通道引导到纤毛，但潜在的机制尚未被充分理解。在这里，我们描述了 Scribble 极性复合物的核心组成部分 DLG1 在调节肾脏上皮细胞纤毛蛋白运输中的作用。在小鼠肾脏中条件性敲除 Dlg1 会导致纤毛伸长和囊肿形成，基于细胞的邻近标记蛋白质组学和荧光显微镜显示，在 DLG1 缺失的情况下，纤毛蛋白组发生改变。具体来说，与对照细胞相比，retromer 相关蛋白 SDCCAG3、IFT20 和多囊蛋白-2（PC2）在 DLG1 缺陷细胞的纤毛中减少。这种表型在体内重现，通过重新表达野生型 DLG1 可挽救，但不能挽救与先天性肾和尿路畸形（CAKUT）相关的 DLG1 变体 p.T489R。最后，生化方法和 Alpha Fold 建模表明，SDCCAG3 和 IFT20 形成一个复合物，至少间接地与 DLG1 相关。我们的工作确定了 DLG1 在调节纤毛蛋白组成中的关键作用，并表明 p.T489R DLG1 变体的纤毛功能障碍可能导致 CAKUT。
