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Subcellular localization of rat gastric phospholipase A2
R Grataroli1, E Termine, H Portugal
1Institut National de la Santé et de la Recherche Médicale, Unité 130, Marseille, France.
Biochimica Et Biophysica Acta
|March 12, 1991
Summary
Gastric phospholipase A2 is primarily found in the apical plasma membrane of stomach mucosa. This enzyme plays a key role in releasing arachidonic acid from membrane phospholipids like phosphatidylcholine and phosphatidylethanolamine.
Area of Science:
- Gastroenterology
- Cell Biology
- Biochemistry
Background:
- Gastric mucosal phospholipase A2 (PLA2) is involved in cellular signaling and inflammation.
- Understanding its subcellular localization is crucial for elucidating its function in gastric physiology.
Purpose of the Study:
- To investigate the subcellular localization and biochemical characteristics of gastric mucosal PLA2.
- To identify the specific membrane fraction associated with PLA2 activity.
Main Methods:
- Subcellular fractionation of gastric mucosa followed by ultracentrifugation on a sucrose gradient.
- Analysis of PLA2 activity, substrate specificity, and association with membrane markers.
Main Results:
- Gastric PLA2 activity was mainly enriched in the 105,000 x g pellet, containing microsomes and plasma membranes.
- Ultracentrifugation revealed PLA2 co-sedimentation with apical plasma membrane markers.
- The enzyme exhibited similar biochemical properties across various fractions, suggesting membrane association.
Conclusions:
- Gastric PLA2 is predominantly associated with the apical plasma membrane.
- The apical plasma membrane is likely the primary site for PLA2-mediated arachidonic acid release in the gastric mucosa.
- Lysophospholipase shares a similar localization, while acyltransferase is found in heavy microsomes.