Protein phosphorylation, at specific amino acid residues, is important for the regulation of many cellular processes including cell cycle progression and division, signal transduction, and apoptosis. The phosphorylation is usually a transfer reaction of the terminal phosphate group from ATP to the protein substrate. The specific structure in the target substrate to which the phosphate is transferred is a tyrosine, serine or threonine residue. Since these amino acid residues are the target structures for the phosphoryl transfer, and since most kinases target either tyrosine or both serine and threonine, these protein kinase enzymes are commonly referred to as tyrosine kinases or serine/threonine (S/T) kinases. The phosphorylation reactions, and counteracting phosphatase reactions, on the tyrosine, serine and threonine residues are involved in many cellular processes that underlie responses to diverse intracellular signals, regulation of cellular functions, and activation or deactivation of cellular processes. A cascade of protein kinases often function in intracellular signal transduction. Protein kinases can be found integrated into the plasma membrane, as cytoplasmic enzymes or localized in the nucleus, often as components of enzyme complexes. In many instances, these protein kinases are an essential element of enzyme and structural protein complexes that determine where and when a cellular process occurs within a cell. Given the importance and diversity of protein kinase function, it is not surprising that phosphorylation events are required in cellular processes associated with many diseases such as cancer, diabetes, inflammation, and hypertension.
The identification of effective small molecules that specifically inhibit protein kinases involved in abnormal or inappropriate cell proliferation, signaling, differentiation, protein production, or metabolism is therefore desirable. The identification of methods and compounds that specifically inhibit the function of kinases that are involved in immune modulation or proliferative disorders is particularly desirable.
The present invention provides novel compounds that inhibit one or more receptor, or non-receptor, tyrosine or S/T kinase.