| First Author | Shum WW | Year | 2011 |
| Journal | Am J Physiol Cell Physiol | Volume | 301 |
| Issue | 1 | Pages | C31-43 |
| PubMed ID | 21411727 | Mgi Jnum | J:175672 |
| Mgi Id | MGI:5286827 | Doi | 10.1152/ajpcell.00198.2010 |
| Citation | Shum WW, et al. (2011) Regulation of V-ATPase recycling via a RhoA- and ROCKII-dependent pathway in epididymal clear cells. Am J Physiol Cell Physiol 301(1):C31-43 |
| abstractText | Luminal acidification in the epididymis is critical for sperm maturation and storage. Clear cells express the vacuolar H(+)-ATPase (V-ATPase) in their apical membrane and are major contributors to proton secretion. We showed that this process is regulated via recycling of V-ATPase-containing vesicles. We now report that RhoA and its effector ROCKII are enriched in rat epididymal clear cells. In addition, cortical F-actin was detected beneath the apical membrane and along the lateral membrane of 'resting' clear cells using a pan-actin antibody or phalloidin-TRITC. In vivo luminal perfusion of the cauda epididymal tubule with the ROCK inhibitors Y27632 (10-30 muM) and HA1077 (30 muM) or with the cell-permeable Rho inhibitor Clostridium botulinum C3 transferase (3.75 mug/ml) induced the apical membrane accumulation of V-ATPase and extension of V-ATPase-labeled microvilli in clear cells. However, these newly formed microvilli were devoid of ROCKII. In addition, Y27632 (30 muM) or HA1077 (30 muM) decreased the ratio of F-actin to G-actin detected by Western blot analysis in epididymal epithelial cells, and Y27632 also decreased the ratio of F-actin to G-actin in clear cells isolated by fluorescence activated cell sorting from B1-enhanced green fluorescence protein (EGFP) transgenic mice. These results provide evidence that depolymerization of the cortical actin cytoskeleton via inhibition of RhoA or its effector ROCKII favors the recruitment of V-ATPase from the cytosolic compartment into the apical membrane in clear cells. In addition, our data suggest that the RhoA-ROCKII pathway is not locally involved in the elongation of apical microvilli. We propose that inhibition of RhoA-ROCKII might be part of the intracellular signaling cascade that is triggered upon agonist-induced apical membrane V-ATPase accumulation. |
