ILK and Cytoskeletal Architecture: An Important Determinant of AQP2 Recycling and Subsequent Entry into the Exocytotic Pathway.

ILK and Cytoskeletal Architecture: An Important Determinant of AQP2 Recycling and Subsequent Entry into the Exocytotic Pathway. Am J Physiol Renal Physiol. 2016 Oct 19;:ajprenal.00336.2016 Authors: Mamuya FA, Cano-Peñalver JL, Li WU, Rodriguez-Puyol D, Rodríguez-Puyol M, Brown D, de Frutos S, Lu HJ Abstract Within the past decade tremendous efforts have been made to understand the mechanism behind aquaporin-2 (AQP2) water channel trafficking and recycling, in order to open a path towards effective diabetes insipidus therapeutics. A recent study has shown that Integrin-Linked Kinase (ILK) conditional-knockdown mice developed polyuria along with decreased expression of AQP2. To understand whether ILK also regulates AQP2 trafficking in kidney tubular cells, we performed in vitro analysis using LLCPK1 cells stably expressing rat AQP2 (LLC-AQP2 cells). Upon treatment of LLC-AQP2 cells with ILK inhibitor cpd22 and ILK-siRNA, we observed increased accumulation of AQP2 in the perinuclear region, without any significant increase in the rate of endocytosis. This perinuclear accumulation did not occur in cells expressing a serine-256-aspartic acid mutation that retains AQP2 in the plasma membrane. We then examined clathrin-mediated endocytosis after ILK inhibition using rhodamine-conjugated transferrin. Despite no differences in overall transferrin endocytosis, the endocytosed transferrin also accumulated in the perinuclear region where it co...
Source: Am J Physiol Renal P... - Category: Urology & Nephrology Authors: Tags: Am J Physiol Renal Physiol Source Type: research