Lipid phosphate phosphohydrolase (LPP) has recently been proposed to have roles in signal transduction, acting sequentially to phospholipase D (PLD) and in attenuating the effects of phospholipid growth factors on cellular proliferation. In this study, LPP activity is reported to be enriched in lipid-rich signalling platforms isolated from rat lung tissue, isolated rat type II cells and type II cell-mouse lung epithelial cell lines (MLE12 and MLE15). Lung and cell line caveolin-enriched domains (CEDs), prepared on the basis of their detergent-insolubility in Triton X-100, contain caveolin-1 and protein kinase C isoforms. The LPP3 isoform was predominantly localized to rat lung CEDs. These lipid-rich domains, including those from isolated rat type II cells, were enriched both in phosphatidylcholine plus sphingomyelin (PC+SM) and cholesterol. Saponin treatment of MLE15 cells shifted the LPP activity, cholesterol, PC+SM and caveolin-1 from lipid microdomains to detergent-soluble fractions. Elevated LPP activity and LPP1/1a protein are present in caveolae from MLE15 cells prepared using the cationic-colloidal-silica method. In contrast, total plasma membranes had a higher abundance of LPP1/1a protein with low LPP activity. Phorbol ester treatment caused a 3.8-fold increase in LPP specific activity in MLE12 CEDs. Thus the activated form of LPP1/1a may be recruited into caveolae/rafts. Transdifferentiation of type II cells into a type I-like cell demonstrated enrichment in caveolin-1 levels and LPP activity. These results indicate that LPP is localized in caveolae and/or rafts in lung tissue, isolated type II cells and type II cell lines and is consistent with a role for LPP in both caveolae/raft signalling and caveolar dynamics.
Skip Nav Destination
Article navigation
September 2001
- PDF Icon PDF LinkFront Matter
Research Article|
September 10 2001
Pulmonary lipid phosphate phosphohydrolase in plasma membrane signalling platforms
Meera NANJUNDAN;
Meera NANJUNDAN
∗Department of Biochemistry, Health Sciences Building, The University of Western Ontario, London, ON, Canada, N6A 5C1
†Department of Obstetrics and Gynaecology, London Health Sciences Centre, University Campus, The University of Western Ontario, 339 Windermere Rd, London, ON, Canada, N6A 5A5
Search for other works by this author on:
Fred POSSMAYER
Fred POSSMAYER
1
∗Department of Biochemistry, Health Sciences Building, The University of Western Ontario, London, ON, Canada, N6A 5C1
†Department of Obstetrics and Gynaecology, London Health Sciences Centre, University Campus, The University of Western Ontario, 339 Windermere Rd, London, ON, Canada, N6A 5A5
1To whom correspondence should be addressed (e-mail fpossmay@uwo.ca).
Search for other works by this author on:
Publisher: Portland Press Ltd
Received:
February 02 2001
Revision Received:
May 18 2001
Accepted:
July 05 2001
Online ISSN: 1470-8728
Print ISSN: 0264-6021
The Biochemical Society, London ©2001
2001
Biochem J (2001) 358 (3): 637–646.
Article history
Received:
February 02 2001
Revision Received:
May 18 2001
Accepted:
July 05 2001
Citation
Meera NANJUNDAN, Fred POSSMAYER; Pulmonary lipid phosphate phosphohydrolase in plasma membrane signalling platforms. Biochem J 15 September 2001; 358 (3): 637–646. doi: https://doi.org/10.1042/bj3580637
Download citation file:
Sign in
Don't already have an account? Register
Sign in to your personal account
You could not be signed in. Please check your email address / username and password and try again.
Captcha Validation Error. Please try again.