Figure 1.

Role of Fak and acyl-PO₄in S. aureus lipid metabolism. Fak is composed of two interacting proteins. FakA is the kinase protein that phosphorylates the FA bound to FakB. FakB is a FA binding protein that picks up FA at the membrane and shuttles them to FakA. Acyl-PO₄ bound to FakB can exchange with a FA in the membrane if it is present. The reversible PlsX reaction transfers the acyl-PO₄ from FakB to ACP. Acyl-ACP may be elongated by FASII or be used by PlsC to form phosphatidic acid (PA), the precursor to all phospholipids in S. aureus. FakB(acyl-PO₄) is a substrate for the glycerol-phosphate acyltransferase (PlsY) to form lysophosphatidic acid (LPA) in the first step of phospholipid synthesis. acyl-PO4, fatty acyl phosphate; FA, fatty acid; Fak, fatty acid kinase; FakA, kinase component of fatty acid kinase; FakB, fatty acid binding protein component of fatty acid kinase; FASII, type II fatty acid synthase.