This is particularly problematic for proteins containing multiple sites of phosphorylation, as each could be independently modulated by different kinases or phosphatases as a function of various stimuli.
Vaccinia-related kinase-2 (VRK2) is a novel human kinase that can modulate different signaling pathways.
PP2A has been implicated in a multitude of signalling cascades that control cell proliferation, division, differentiation, apoptosis, metabolism, adhesion and migration and is thought to modulate the activity of over 30 different kinases [reviewed in (4)].
It has been shown that PPAR γ may be phosphorylated by different kinases including AMPK, which can modulate PPAR γ activity.
The protein kinase family is one of the largest protein families in human, comprising 518 different kinases that function as on/off switches in cellular signaling pathways and modulate almost all basic cellular activities.
Interestingly, the phosphorylation of p27 on its last residue threonine 198 (T198) by different kinases [16] [17] has been proposed to control not only its stability [18] but also to modulate its activity in the regulation of cell motility [17].
It is known to modulate different pathways involved in cell growth, cell development, tissue inflammation and cellular chemotaxis due to its well described function to dephosphorylate receptor tyrosine kinases (reviewed in [ 1]).
Here, we identify ten new Thr4 kinases from different kinase structural groups.
Activated Akt kinase plays a crucial role in antiapoptosis by modulating different signal downstream events (Fig. 1).
Src family kinases such as Lyn are important signaling intermediaries, relaying and modulating different inputs to regulate various outputs, such as proliferation, differentiation, apoptosis, migration and metabolism.
