Class Receptor Receptor-Linked G-Protein Coupled Ligand Gated Kinases Kinases Receptors lon Channels Insulin Growth Hormone Peptides Neurotransmitters Ligands Growth Factors Prolactin. Neurotransmitters Amino Acids Cytokines Prostaglandins General Structure 器ReE Protein Tyrosine or Receptor Associated 2nd Messenger Serine Kinase Tyrosine Kinase (cAMP, IP, lon) Cytoplasmic Protein Kinases Phosphorylation Mediated Actions Non-Phosphorylation Mediated Actions10