Serine and threonine phosphorylation

Various hormonal agents (eg, glucocorticoids) lower the affinity of insulin receptors for insulin growth hormone in excess increases this affinity slightly. Aberrant serine and threonine phosphorylation of the insulin receptor subunits or IRS molecules may result in insulin resistance and functional receptor down-regulation. 

Software predictions suggest a number of potential phosphorylation sites in the coronin 7 protein. The highest E value predictions are for potential MAP kinase phosphorylation sites at serine residue 442 and threonines 497 and 733, cdc2 sites at S-450 and S-775, cdk5 at S-437, PKC sites at S-7, S-465 and T-654 and Src sites at tyrosine residues 288 and 758. Not surprisingly, many serine and threonine phosphorylation predictions concentrate in the low complexity PST-enriched region. Although it remains to be elucidated which of the predicted sites are relevant in vivo, at least some of them have been experimentally demonstrated to be phosphorylated in vitro (see below). 

Catterall 1 agree that you should think about phosphorylation, and not only serine and threonine phosphorylation but also tyrosine phosphorylation. In... 

The insulin receptor system, which functions independently of the G protein, causes proteins to be phosphorylated on tyrosine groups in contrast with the serine and threonine phosphorylations due to cAMP dependent protein kinase (Fig. 16.4). A number of tyrosine phosphorylations occur, including autophosphorylation of the insulin receptor, per se, which may have some important relationship to down regulation of the insulin receptors during continual high levels of insulin. The tyrosine kinase system has not been studied in the same detail as have cAMP,... 

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