Interacting selectively with a nucleotide, any compound consisting of a nucleoside that is esterified with (ortho)phosphate or an oligophosphate at any hydroxyl group on the ribose or deoxyribose moiety [goid 166] [evidence IEA]; Catalysis of the reaction: ATP + a protein-L-tyrosine = ADP + a protein-L-tyrosine phosphate, to initiate a change in cell activity [goid 4714] [evidence IEA]; Combining with an extracellular or intracellular messenger to initiate a change in cell activity [goid 4872] [evidence IEA]; Interacting selectively with ATP, adenosine 5'-triphosphate, a universally important coenzyme and enzyme regulator [goid 5524] [evidence IEA]; Catalysis of the transfer of a group, e.g. a methyl group, glycosyl group, acyl group, phosphorus-containing, or other groups, from one compound (generally regarded as the donor) to another compound (generally regarded as the acceptor). Transferase is the systematic name for any enzyme of EC class 2 [goid 16740] [evidence IEA]; Interacting selectively with a nucleotide, any compound consisting of a nucleoside that is esterified with (ortho)phosphate or an oligophosphate at any hydroxyl group on the ribose or deoxyribose moiety [goid 166] [evidence IEA];  [goid 4716] [pmid 6849137] [evidence IDA]; Combining with an extracellular or intracellular messenger to initiate a change in cell activity [goid 4872] [evidence IEA]; Combining with insulin to initiate a change in cell activity [goid 5009] [pmid 8440175] [evidence IDA]; Interacting selectively with the insulin-like growth factor receptor [goid 5159] [pmid 8452530] [evidence IDA]; Interacting selectively with ATP, adenosine 5'-triphosphate, a universally important coenzyme and enzyme regulator [goid 5524] [evidence IEA]; Interacting selectively with GTP, guanosine triphosphate [goid 5525] [pmid 9092559] [evidence IDA]; Catalysis of the transfer of a group, e.g. a methyl group, glycosyl group, acyl group, phosphorus-containing, or other groups, from one compound (generally regarded as the donor) to another compound (generally regarded as the acceptor). Transferase is the systematic name for any enzyme of EC class 2 [goid 16740] [evidence IEA]; Interacting selectively with insulin-like growth factor I [goid 31994] [pmid 8452530] [evidence IPI]; Interacting selectively with insulin-like growth factor II [goid 31995] [pmid 12138094] [evidence IPI]; Interacting selectively with a SH2 domain (Src homology 2) of a protein, a protein domain of about 100 amino-acid residues and belonging to the alpha + beta domain class [goid 42169] [pmid 8276809] [evidence IPI]; Interacting selectively with a phosphoinositide 3-kinase, any enzyme that catalyzes the addition of a phosphate group to an inositol lipid at the 3' position of the inositol ring [goid 43548] [pmid 8276809] [evidence IPI]; Interacting selectively with a phosphoinositide 3-kinase, any enzyme that catalyzes the addition of a phosphate group to an inositol lipid at the 3' position of the inositol ring [goid 43548] [pmid 7537849] [evidence IPI]; Interacting selectively with insulin, a polypeptide hormone produced by the islets of Langerhans of the pancreas in mammals, and by the homologous organs of other organisms [goid 43559] [pmid 8440175] [evidence IDA]; Interacting selectively with any of the insulin receptor substrate (IRS) proteins, adaptor proteins that bind to the transphosphorylated insulin and insulin-like growth factor receptors, are themselves phosphorylated and in turn recruit SH2 domain-containing signaling molecules to form a productive signaling complex [goid 43560] [pmid 7559478] [evidence IPI]; Interacting selectively with any of the insulin receptor substrate (IRS) proteins, adaptor proteins that bind to the transphosphorylated insulin and insulin-like growth factor receptors, are themselves phosphorylated and in turn recruit SH2 domain-containing signaling molecules to form a productive signaling complex [goid 43560] [pmid 7537849] [evidence IPI]; Interacting selectively with a phosphotyrosine-binding (PTB) domain of a protein [goid 51425] [pmid 7559478] [evidence IPI]