| First Author | Sun-Wada GH | Year | 2003 |
| Journal | J Biol Chem | Volume | 278 |
| Issue | 45 | Pages | 44843-51 |
| PubMed ID | 12947086 | Mgi Jnum | J:86572 |
| Mgi Id | MGI:2680782 | Doi | 10.1074/jbc.M307197200 |
| Citation | Sun-Wada GH, et al. (2003) Mouse proton pump ATPase C subunit isoforms (C2-a and C2-b) specifically expressed in kidney and lung. J Biol Chem 278(45):44843-51 |
| abstractText | The vacuolar-type H+-ATPases (V-ATPases) are multimeric proton pumps involved in a wide variety of physiological processes. We have identified two alternative splicing variants of C2 subunit isoforms: C2-a, a lung-specific isoform containing a 46-amino acid insertion, and C2-b, a kidney-specific isoform without the insert. Immunohistochemistry with isoform-specific antibodies revealed that V-ATPase with C2-a is localized specifically in lamellar bodies of type II alveolar cells, whereas the C2-b isoform is found in the plasma membranes of renal alpha and beta intercalated cells. Immunoprecipitation combined with immunohistological analysis revealed that C2-b together with other kidney-specific isoforms was selectively assembled to form a unique proton pump in intercalated cells. Furthermore, a chimeric yeast V-ATPase with mouse the C2-a or C2-b isoform showed a lower Km(ATP) and lower proton transport activity than that with C1 or Vma5p (yeast C subunit). These results suggest that V-ATPases with the C2-a and C2-b isoform are involved in luminal acidification of lamellar bodies and regulation of the renal acid-base balance, respectively. |
