For example, the conjugation of ubiquitin to a substrate can modulate its activity, target it for degradation, alter its cellular location, or determine its interaction with other proteins [2].
AMPK is a substrate for kinases such as LKB1 and CAMKK2, which modulate its activity by phosphorylation of the activation loop on both alpha subunits at threonine 172.
It can cleave a number of extracellular substrates, including proteoglycans, to release active glycosaminoglycans [ 50], which in turn modulate its activity.
Guanosine tetraphosphate appears to exert most of its physiological effects by direct or indirect transcriptional control of target genes and binds near the active centre of RNA polymerase (RNAP) to modulate its activity, resulting in the direct repression of stable RNA operons (for review see [ 18].
The cytosolic sensory kinase DegS does not receive a single predominant input signal like most two-component kinases, instead it integrates a wide array of metabolic inputs that modulate its activity.
It forms part of a sub-module of four proteins able to associate with the core mediator complex to modulate its activity.
Mimicking natural estrogens, they bind to estrogen receptor and modulate its activity.
Much remains to be learned about the partner proteins and trafficking pathways that determine the sodium pump's subcellular distribution and modulate its activity.
Among the obtained products, T1, T3 and T7 specifically bind VEGFR2 TK and modulate its activity by concentration dependent manner.
To our knowledge, this study is the first report to demonstrate that the IAV NS1 protein can directly interact with the cellular protein Rac1 and modulate its activity via post-translational modifications to regulate IAV replication.
These ProGP molecules differ in the orientation of the two receptor agonists and, in addition, ProGP-4 contains a fetal liver tyrosine kinase-3 receptor agonist that has been circularly permuted to modulate its activity.
