FIG 1.

The major source of lipids in human serum is from LDL particles that contain cholesteryl esters, unesterified cholesterol, triglycerides, and phospholipids. S. aureus secretes at least two lipases, Sal1 and Geh, that release free fatty acids (FAs) from lipids found in serum and LDL. These free fatty acids can be incorporated into S. aureus membrane lipids through the FakA/B and PlsXY systems, with or without further elongation in type II fatty acid synthesis (FASII). ACP, acyl carrier protein; G3P, glycerol 3-phosphate; PA, phosphatidic acid.