Protein phosphorylation on @entity563 , XXXX , and @entity669 residues modulates membrane-protein interactions and transcriptional regulation in @entity2491 .

@entity2491 @entity2227 @entity563 @entity1521 @entity1889 @entity669
There exists a plethora of @entity669 kinases that play essential roles in regulation of eukaryotic proteins. Several dual specificity kinases that phosphorylate proteins on @entity1889 , @entity563 , and @entity669 residues also play critical roles in eukaryotic phosphorylation cascades. In contrast, very few prokaryotic proteins have been shown to be phosphorylated on @entity669 residues, and the functions of the rare examples remain obscure. Furthermore, no dual specificity kinases have been described in prokaryotes. Our results indicate that PutA protein from the bacterium @entity2491 autophosphorylates on several @entity1889 , @entity563 , and @entity669 residues. PutA protein both represses the @entity1521 utilization (put) operon and degrades @entity1521 to @entity2227 . These two opposing functions are regulated by the availability of @entity1521 and the membrane sites needed for the @entity1521 dehydrogenase activity of PutA protein. In addition, these functions are modulated by phosphorylation of PutA protein. The rate of dephosphorylation of PutA protein is determined by the availability of @entity1521 and membranes. Dephosphorylated PutA protein has a higher DNA binding affinity than the phosphorylated protein and thus may prevent toxic overexpression of PutA protein in the absence of available membrane sites.
