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Regulation of vacuolar H+‐ATPase (V‐ATPase) recycling via a RhoA‐dependent pathway in epididymal clear cells
Author(s) -
Shum Winnie,
Da Silva Nicolas,
Brown Dennis,
Breton Sylvie
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.796.16
Subject(s) - rhoa , microbiology and biotechnology , actin , apical membrane , chemistry , atpase , cytoskeleton , phalloidin , intracellular , biology , biochemistry , signal transduction , cell , membrane , enzyme
The V‐ATPase in clear cells is important for luminal acidification in the epididymis, a process that is critical for sperm maturation and storage. We showed that proton secretion in these cells is regulated via V‐ATPase recycling. We now find that RhoA is enriched in clear cells where it is located mainly in the sub‐apical region. In addition, cortical F‐actin was detected beneath the apical membrane of clear cells using a pan‐actin antibody or phalloidin‐TRITC on epididymis sections. In epididymal tubules perfused in vivo, agents known to stimulate V‐ATPase membrane accumulation (1mM cpt‐cAMP, 1mM cpt‐cGMP, 1mM SNP, or 100µM ANGII) significantly reduced the intensity of cortical F‐actin staining. The Rho‐Kinase (ROCK) inhibitor Y27632 (10µM) or the cell permeable Rho inhibitor, Clostridium C3 transferase (3.75 µg/ml) also decreased the intensity of sub‐apical F‐actin staining and induced apical membrane V‐ATPase accumulation. These results provide evidence that depolymerization of the actin cytoskeleton via inhibition of RhoA or its effector ROCK favors apical membrane V‐ATPase accumulation. Thus, cAMP‐ or cGMP‐dependent inhibition of RhoA might be part of the intracellular signaling cascade that is triggered upon agonist‐induced apical membrane V‐ATPase accumulation and subsequent activation of V‐ATPase‐dependent proton secretion in clear cells. This research is supported by NIH grant DK38452.