Posttranslational modification of proteins by phosphorylation is a universal mechanism for regulating diverse biological functions. Recognition that many cellular proteins are reversibly phosphorylated in response to external stimuli or intracellular signals has generated an ongoing interest in identifying and characterizing plant protein kinases and protein phosphatases that modulate the phosp...

In addition to the major serine/threonine-specific phosphoprotein phosphatase, Mg(2+)-dependent phosphoprotein phosphatase, and protein tyrosine phosphatase families, there are novel protein phosphatases, including enzymes with aspartic acid-based catalysis and subfamilies of protein tyrosine phosphatases, whose evolutionary history and representation in plants is poorly characterized. We have ...

The molecular mechanisms of signal transduction have been at the focus of increasingly intense scientific research. As a result, our understanding of protein tyrosine kinase-mediated signaling has advanced at an unprecedented pace during the past decade. In contrast, the study of protein tyrosine phosphatases has lagged behind, but is now gathering momentum and is predicted to become a "hot top...

1 (1-1) and inhibitor-2 (1-2), and preferentially dephosphorylate the /3-subunit of phosphorylase kinase, whereas type-2 phosphatases are insensitive to the heat-stable inhibitors and preferentially dephosphorylate the x-subunit of phosphorylase kinase [1,2]. Type-2 phosphatases can be further subdivided into spontaneously active (PP2A), Ca2l-dependent (PP2B) and Mg2+dependent (PP2C) classes. T...

Cell cycle transitions depend on protein phosphorylation and dephosphorylation. The discovery of cyclin-dependent kinases (CDKs) and their mode of activation by their cyclin partners explained many important aspects of cell cycle control. As the cell cycle is basically a series of recurrences of a defined set of events, protein phosphatases must obviously be as important as kinases. However, ou...

Acute myeloid leukemia (AML) is a highly malignant disease of myeloid cell line. AML is the most frequent adult leukemia with inadequate treatment possibility. The protein phosphatases are critical regulators of cell signaling, and deregulation of protein phosphatases always contribute to cell transformation. Although many studies established a relationship between protein phosphatases and leuk...