Skip Navigation

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrow Search for citing articles in:
ISI Web of Science (12)
Right arrowRequest Permissions
Right arrow Disclaimer
Google Scholar
Right arrow Articles by Vareesangthip, K.
Right arrow Articles by Wilkinson, R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Vareesangthip, K.
Right arrow Articles by Wilkinson, R.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Nephrol Dial Transplant (1995) 10: 2219-2223
© 1995 European Renal Association-European Dialysis and Transplant Association

research-article

Abnormal effect of thiol groups on erythrocyte Na/Li countertransport kinetics in adult polycystic kidney disease

K. Vareesangthip, T. H. Thomas and R. Wilkinson

Department of Medicine (Nephrology), University of Newcastle-upon-Tyne UK

Correspondence and offprint requests to: Correspondence and offprint requests to: Dr T. H. Thomas, Department of Medicine, Medical School, Framlington Place, Newcastle-upon-Tyne, NE2 4HH, UK

BACKGROUND: Evidence suggests that in adult polycystic kidney disease (APCKD) there is abnormal membrane organisation that involves cytoskeletal proteins and affects ion-transport proteins. The possibility of detecting a membrane organisation defect in erythro-cytes from APCKD patients was investigated.

METHODS: Na/Li countertransport (CT) kinetics were measured in erythrocytes from APCKD patients compared with normal controls. The modulation of Na/Li CT kinetics by key membrane thiol groups and by dissociation of spectrin by heating was studied.

RESULTS: In erythrocytes from APCKD compared to normal subjects the Km of Na/Li CT was lower (64 SEM 3v 90 SEM 3 mmol Na/1, P<0.001) and Vmax/Km was higher (6.8 SEM 0.6 v 5.3 SEM 0.4 (x 10–3), P<0.05). In erythrocytes from normal subjects, after N-ethylmaleimide (NEM) treatment in cho-line medium, Km of Na/Li CT was reduced and Vmax/Km increased (59 SEM 5, 8.2 SEM 0.4 (x 10–3), P<0.001) but there was no effect on these kinetic parameters in erythrocytes from APCKD. The effect of heating was similar to that of NEM in choline medium. In normal controls after NEM treatment in sodium medium both Km and Vmax were reduced whereas in APCKD Vmax was reduced but Km was unchanged.

CONCLUSIONS: In APCKD the effect of a key membrane thiol group on Na association with Na/Li CT was absent and the effect of spectrin dissociation was similarily abnormal. A second thiol group effect on the Vmax of Na/Li CT was normal. The results are consistent with a thiol-protein linked to the spectrin cytoskeleton that modulates Na/Li CT and is abnormal in APCKD.

Keywords: adult polycystic kidney disease; cytoskeleton; erythrocyte; N-ethylmaleimide; sodium lithium countertransport; thiol groups


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer:
Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.