Pdcd10-Stk24/25 complex controls kidney water reabsorption by regulating Aqp2 membrane targeting
Rui Wang, Shi-Ting Wu, Xi Yang, Yude Qian, Jaesung P. Choi, Rui Gao, Siliang Song, Yixuan Wang, Tao Zhuang, Justin J.L. Wong, Yuzhen Zhang, Zhiming Han, Hua A. Lu, Stephen I. Alexander, Renjing Liu, Yin Xia, Xiangjian Zheng
Rui Wang, Shi-Ting Wu, Xi Yang, Yude Qian, Jaesung P. Choi, Rui Gao, Siliang Song, Yixuan Wang, Tao Zhuang, Justin J.L. Wong, Yuzhen Zhang, Zhiming Han, Hua A. Lu, Stephen I. Alexander, Renjing Liu, Yin Xia, Xiangjian Zheng
View: Text | PDF
Research Article Nephrology

Pdcd10-Stk24/25 complex controls kidney water reabsorption by regulating Aqp2 membrane targeting

Abstract

PDCD10, also known as CCM3, is a gene found to be associated with the human disease cerebral cavernous malformations (CCMs). PDCD10 forms a complex with GCKIII kinases including STK24, STK25, and MST4. Studies in C. elegans and Drosophila have shown a pivotal role of the PDCD10-GCKIII complex in maintaining epithelial integrity. Here, we found that mice deficient of Pdcd10 or Stk24/25 in the kidney tubules developed polyuria and displayed increased water consumption. Although the expression levels of aquaporin genes were not decreased, the levels of total and phosphorylated aquaporin 2 (Aqp2) protein in the apical membrane of tubular epithelial cells were decreased in Pdcd10- and Stk24/25-deficient mice. This loss of Aqp2 was associated with increased expression and membrane targeting of Ezrin and phosphorylated Ezrin, Radixin, Moesin (p-ERM) proteins and impaired intracellular vesicle trafficking. Treatment with Erlotinib, a tyrosine kinase inhibitor promoting exocytosis and inhibiting endocytosis, normalized the expression level and membrane abundance of Aqp2 protein, and partially rescued the water reabsorption defect observed in the Pdcd10-deficient mice. Our current study identified the PDCD10-STK-ERM signaling pathway as a potentially novel pathway required for water balance control by regulating vesicle trafficking and protein abundance of AQP2 in the kidneys.

Authors

Rui Wang, Shi-Ting Wu, Xi Yang, Yude Qian, Jaesung P. Choi, Rui Gao, Siliang Song, Yixuan Wang, Tao Zhuang, Justin J.L. Wong, Yuzhen Zhang, Zhiming Han, Hua A. Lu, Stephen I. Alexander, Renjing Liu, Yin Xia, Xiangjian Zheng

×

Figure 5

Pdcd10 regulates vesicle trafficking in cultured collecting duct cells.

Options: View larger image (or click on image) Download as PowerPoint
Pdcd10 regulates vesicle trafficking in cultured collecting duct cells. ...
(A and B) Immunostaining of Aqp2(green) and Rab11a (red) (A), and Aqp2(green) and GM130 (red) (B), of si-Cont and si-Pdcd10–treated mCCDCl1 cells transduced with lentivirus expressing Aqp2. The square panels represent xy-sections, and the smaller horizontal strips at the bottom of each square panel represents z-sections of reconstructed 3-D confocal stacks at the at the positions indicated by the yellow dashed lines in the xy planes. (C) Representative images showing the internalization of dextran (red) in si-Cont and si-Pdcd10–transfected mCCDCl1 cells, and si-Pdcd10–transfected mCCDCl1 cells treated with Erlotinib or methyl-β-cyclodextrin (MβCD). The middle square panels represent higher magnification of the selected areas. The z-sections of the cells are indicated by the dashed line at the bottom of each square panel. (D) The quantifications of the mean cellular dextran fluorescence intensity; each dot represents fluorescence intensity normalized to si-Cont (si-Cont and si-Pdcd10, n = 4; si-Pdcd10 + Erlo and si-Pdcd10 + MβCD, n = 3). (E) Immunostaining of Ezrin (green) and p-ERM (red) in the si-Cont and si-Pdcd10–treated mCCDCl1 cells. The middle square panels represent higher magnification of the selected areas. The square panels represent xy-sections, and the horizontal strips at the bottom of each square panel represent z-sections of reconstructed 3-D confocal stacks. (F) The quantification of mean cellular Ezrin and p-ERM fluorescence intensity; each dot represents fluorescence intensity normalized to si-Cont (n = 6 for each group of Ezrin; si-Cont of p-ERM, n = 5; si-Pdcd10 of p-ERM, n = 4). The n value represents the field of visions in different experiments. (G) The quantification of mean cellular p-ERM fluorescence intensity after normalization with total ezrin abundance. Data are presented as mean ± SEM using unpaired t test (F and G) or 1-way ANOVA (D). ***P < 0.001; **P < 0.01. Original magnification, ×630 (A and C); ×400 (B and E).