A.
Protein kinase A phosphorylates tyrosine residues.
B.
Protein kinase C is activated by cAMP.
C.
The subunit of Gs proteins that activates adenylyl cyclase is the β-subunit.
D.
Lipid-soluble messengers typically act on receptors in the cell cytosol or nucleus.
E.
The binding site of a typical plasma-membrane receptor for its messenger is located on the cytosolic surface of the receptor.