An AKAP-Lbc-RhoA interaction inhibitor promotes the translocation of aquaporin-2 to the plasma membrane of renal collecting duct principal cells
作者:Katharina Schrade、Jessica Tröger、Adeeb Eldahshan、Kerstin Zühlke、Kamal R. Abdul Azeez、Jonathan M. Elkins、Martin Neuenschwander、Andreas Oder、Mohamed Elkewedi、Sarah Jaksch、Karsten Andrae、Jinliang Li、Joao Fernandes、Paul Markus Müller、Stephan Grunwald、Stephen F. Marino、Tanja Vukićević、Jenny Eichhorst、Burkhard Wiesner、Marcus Weber、Michael Kapiloff、Oliver Rocks、Oliver Daumke、Thomas Wieland、Stefan Knapp、Jens Peter von Kries、Enno Klussmann
DOI:10.1371/journal.pone.0191423
日期:——
Stimulation of renal collecting duct principal cells with antidiuretic hormone (arginine-vasopressin, AVP) results in inhibition of the small GTPase RhoA and the enrichment of the water channel aquaporin-2 (AQP2) in the plasma membrane. The membrane insertion facilitates water reabsorption from primary urine and fine-tuning of body water homeostasis. Rho guanine nucleotide exchange factors (GEFs) interact with RhoA, catalyze the exchange of GDP for GTP and thereby activate the GTPase. However, GEFs involved in the control of AQP2 in renal principal cells are unknown. The A-kinase anchoring protein, AKAP-Lbc, possesses GEF activity, specifically activates RhoA, and is expressed in primary renal inner medullary collecting duct principal (IMCD) cells. Through screening of 18,431 small molecules and synthesis of a focused library around one of the hits, we identified an inhibitor of the interaction of AKAP-Lbc and RhoA. This molecule, Scaff10-8, bound to RhoA, inhibited the AKAP-Lbc-mediated RhoA activation but did not interfere with RhoA activation through other GEFs or activities of other members of the Rho family of small GTPases, Rac1 and Cdc42. Scaff10-8 promoted the redistribution of AQP2 from intracellular vesicles to the periphery of IMCD cells. Thus, our data demonstrate an involvement of AKAP-Lbc-mediated RhoA activation in the control of AQP2 trafficking.
抗利尿激素(精氨酸加压素,AVP)刺激肾集合管主细胞后,会抑制小GTP酶RhoA,并在质膜中富集水通道蛋白aquaporin-2(AQP2)。这种膜插入促进了从原尿中重吸收水分,并精细调控体内水平衡。Rho鸟苷酸交换因子(GEFs)与RhoA相互作用,催化GDP与GTP的交换,从而激活GTP酶。然而,参与肾主细胞中AQP2调控的GEFs尚不清楚。A激酶锚定蛋白AKAP-Lbc具有GEF活性,特异性激活RhoA,并且在肾内髓集合管主细胞中表达。通过对18,431个小分子进行筛选,并围绕其中一个候选分子合成焦点库,我们鉴定出了一个抑制AKAP-Lbc与RhoA相互作用的抑制剂。这个分子,Scaff10-8,结合到RhoA上,抑制了AKAP-Lbc介导的RhoA激活,但不干扰通过其他GEFs激活RhoA或Rho家族小GTP酶Rac1和Cdc42的活性。Scaff10-8促进了AQP2从细胞内囊泡向IMCD细胞边缘的重分布。因此,我们的数据表明AKAP-Lbc介导的RhoA激活在AQP2转运调控中的作用。