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Publication Details
AFRICAN RESEARCH NEXUS
SHINING A SPOTLIGHT ON AFRICAN RESEARCH
biochemistry, genetics and molecular biology
Relationship between the inhibition of phosphatidic acid phosphohydrolase-1 by oleate and oleoyl-CoA ester and its apparent translocation
Biochimie, Volume 87, No. 5, Year 2005
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Description
Phosphatidic acid phosphohydrolase-1 (PAP-1) activity is reversibly inhibited by fatty acids and their acyl-CoA esters and it appears paradoxical that these effectors have been reported to increase the liver's esterification capacity by translocating the rate-limiting enzyme PAP-1 from cytosol to the endoplasmic reticulum. Therefore, we have examined the effect of oleate, oleoyl-CoA, and spermine on the activation and translocation of PAP-1 of rat liver. PAP-1 activity is directly inhibited by oleic acid and oleoyl-CoA ester in an allosteric manner, resulting in the formation of inactive PAP-1-fatty acid (or -acyl-CoA) complex, even in the absence of any subcellular structures. Such association/aggregation of PAP-1 can be easily collected by centrifugation and may explain the apparent translocation phenomenon of this enzyme to a particular structure in the presence of fatty acids or acyl-CoA esters as reported in many works. Indeed, incubation of cytosol fraction alone with oleate or oleoyl-CoA at 37°C, followed by centrifugation, induces a significant increase (sevenfold) in PAP-1 activity in the pellet fraction. This displacement is accompanied by an increase in the specific activity of PAP-1 in the pellet fraction. Spermine is less effective than oleate in inducing the displacement of PAP-1 activity from cytosol to the pellet fraction in the absence of any membrane structures. This apparent translocation of PAP-1 is also promoted when homogenate fraction was incubated with oleate prior to the preparation of cytosol and microsomal fraction. Thus, many of the announced factors, including fatty acids, would promote the in vitro association/aggregation of PAP-1 enzyme rather than its translocation, and therefore, re-evaluation of the reported effects on PAP-1 translocation phenomenon is required. It is proposed that fatty acids and their esters would favour β-oxidation over esterification by promoting the forming of inactive associated PAP-1 in situations such as starvation and metabolic stress in which there is an increased supply of fatty acids to the liver. © 2005 Elsevier SAS. All rights reserved.
Authors & Co-Authors
Elabbadi, N.
Morocco, Marakech
Faculté Des Sciences et Techniques Marrakech
United Kingdom, Newcastle
Newcastle University
Day, Christopher P.
United Kingdom, Newcastle
Newcastle University
Gamouh, A.
Morocco, Marakech
Faculté Des Sciences et Techniques Marrakech
Zyad, Abdelmajid
Morocco, Marakech
Faculté Des Sciences et Techniques Marrakech
Yeaman, S. J.
United Kingdom, Newcastle
Newcastle University
Statistics
Citations: 17
Authors: 5
Affiliations: 2
Identifiers
Doi:
10.1016/j.biochi.2005.01.003
ISSN:
03009084
Research Areas
Noncommunicable Diseases