All except one of the following are true about the protein kinase A (PKA) pathway
The principle of enzyme catalysis and lipid structure explains that substrate affinity, transition state stabilization and phospholipid composition govern function. Hence PKA phosphorylates proteins at tyrosine residues fits best because it reflects catalytic efficiency and membrane organization, as documented in authoritative sources on biochemistry.
Ref: Lehninger Principles of Biochemistry, Chapter 9, Lipids and Membranes, explains phospholipid components, glycerol, fatty acids, phosphate group and membrane structure providing foundation for lipid biochemistry.
