we propose that occupation of some cell-surface hormone receptors leads to camp accumulation and the activation of protein kinase in subcellular compartments , with the consequent phosphorylation of specific , rather than all , substrates of protein kinase . circumstances potentially contributing to this specificity include : ( a ) physical and kinetic compartmentation of hormone-receptor-adenylate cyclase complexes non-randomly within the cell membrane ;
C0031715
phosphorylation
C0033640
protein