Effect of Lectins on Protein Kinase Activity

Protein kinases have critical roles for the amplification and distribution of the signals that are sent from the cell surface to the cytoplasm after ligand binding. They are generally classified into two groups: protein-serine/threonine kinases, such as cAMP-dependent protein kinase or casein kinases, and protein-tyrosine kinases (PTKs), such as EGF receptor kinase or p60^src . Although the amount of protein-tyrosine phosphorylation is much less than that of proteinserine/threonine phosphorylation, PTKs are particularly important in the control of cell proliferation and differentiation. PTKs have themselves been divided into two groups. the transmembrane receptor group and nonreceptor group.