Networks of extracellular and intracellular signals
Role of cell structure in intracellular communication
The plasma-membrane receptors and GTP-binding proteins
The protein kinases and phosphatases
The inositol polyphosphates and diacylglycerols
The intermediary metabolites
Metabolites of arachidonic acid
Sequence-specific DNA-binding proteins
Interactions between pathways of intracellular communication.