Distribution of Rab GTPases in mouse kidney and comparison with vacuolar H+-ATPase

Nephron Physiol. 2005;100(3):p31-42. doi: 10.1159/000085114. Epub 2005 Apr 15.

Abstract

Background: Vacuolar H+-ATPases (V-ATPases) are essential for renal bicarbonate transport in both the proximal and distal nephron. Regulation of proton transport occurs, in part, by vesicle-mediated traffic of V-ATPases between intracellular vacuoles and the plasma membrane. Although the proteins involved in regulated V-ATPase traffic are largely unknown, Rab GTPases have a central role in the traffic and recycling of other membrane proteins.

Methods: To identify candidate Rab GTPases potentially involved in V-ATPase traffic, immunocytochemical and subcellular fractionation studies were used to evaluate the distribution to sites of abundant V-ATPase of 5 Rab GTPases expressed in kidney, Rab5a, Rab11, Rab13, Rab18, and Rab20.

Results: The immunocytochemical distribution of Rab5a and Rab13 and the subcellular distribution of Rab18 were not compatible with a role in V-ATPase traffic. In contrast, Rab11 colocalized with V-ATPase in apical regions of proximal tubule, and Rab20 colocalized with the enzyme in intercalated cells. Rab11 and Rab20 were enriched in membrane fractions that were also enriched in V-ATPase B2 and B1 subunit isoforms, respectively.

Conclusions: The immunohistochemical data in combination with the membrane fractionation studies are consistent with a potential role for Rab11 and Rab20 in regulating V-ATPase traffic in specific segments of the nephron.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Kidney / metabolism*
  • Male
  • Mice
  • Proton-Translocating ATPases / metabolism*
  • Tissue Distribution
  • Vacuoles / metabolism*
  • rab GTP-Binding Proteins / metabolism*

Substances

  • Proton-Translocating ATPases
  • rab GTP-Binding Proteins