The article reviews the role of protein kinase C (PKC) isoenzymes in signal transduction pathways, emphasizing their divergence in structure, activation, and substrate specificity. PKC is a key enzyme activated by second messengers like DAG and PtdSer, and it plays a central role in regulating gene expression and cellular processes such as proliferation and differentiation. The article discusses the classification of PKC isoenzymes into Ca2+-dependent (cPKCs) and Ca2+-independent (nPKCs) groups, with detailed descriptions of their protein structure, including conserved and variable regions. It highlights the importance of autophosphorylation, proteolytic activation, and substrate specificity in understanding PKC function. The expression patterns of PKC isoenzymes across different tissues and cell types are also explored, along with their intracellular distribution and translocation upon stimulation. The review suggests that the distinct characteristics of PKC isoenzymes contribute to their diverse roles in signal transduction, potentially leading to divergent responses in cellular processes.The article reviews the role of protein kinase C (PKC) isoenzymes in signal transduction pathways, emphasizing their divergence in structure, activation, and substrate specificity. PKC is a key enzyme activated by second messengers like DAG and PtdSer, and it plays a central role in regulating gene expression and cellular processes such as proliferation and differentiation. The article discusses the classification of PKC isoenzymes into Ca2+-dependent (cPKCs) and Ca2+-independent (nPKCs) groups, with detailed descriptions of their protein structure, including conserved and variable regions. It highlights the importance of autophosphorylation, proteolytic activation, and substrate specificity in understanding PKC function. The expression patterns of PKC isoenzymes across different tissues and cell types are also explored, along with their intracellular distribution and translocation upon stimulation. The review suggests that the distinct characteristics of PKC isoenzymes contribute to their diverse roles in signal transduction, potentially leading to divergent responses in cellular processes.