The mechanism regulating radiation-induced anti-apoptotic response, a limiting factor in improving cell radiosensitivity, remains elusive. Mitogen-activated protein kinase (MAPK) phosphatase (MKP)-1 is the major member of MKPs that dephosphorylates and inactivates MAPK. Here we provide the evidence that MKP-1 was negatively bridging between NF-kappaB-mediated prosurvival pathway and c-Jun N-ter...

Monocytic adhesion and chemotaxis are regulated by MAPK pathways, which in turn are controlled by redox-sensitive MAPK phosphatases (MKPs). We recently reported that metabolic disorders prime monocytes for enhanced recruitment into vascular lesions by increasing monocytes' responsiveness to chemoattractants. However, the molecular details of this proatherogenic mechanism were not known. Here we...

Diabetes promotes the S-glutathionylation, inactivation and subsequent degradation of mitogen-activated protein kinase phosphatase 1 (MKP-1) in blood monocytes, and hematopoietic MKP-1-deficiency in atherosclerosis-prone mice accelerates atherosclerotic lesion formation, but the underlying mechanisms were not known. Our aim was to determine the mechanisms through which MKP-1 deficiency in monoc...

OBJECTIVE Mitogen-activated protein kinase phosphatase-1 (MKP-1) is one of several oxidized-l-alpha-1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (Ox-PAPC)-induced genes identified in human aortic endothelial cells (HAEC). We previously reported that MKP-1 activity is required for Ox-PAPC-mediated endothelial/monocyte interactions; however, an in vivo role of MKP-1 in atherogenesis ...

Inhibitors of the proteasome, a multicatalytic proteinase complex responsible for intracellular proteolysis, activate programmed cell death in part through the c-Jun-N-terminal kinase (JNK). Proteasome inhibitors also induce mitogen-activated protein kinase phosphatase-1 (MKP-1), however, which can inactivate JNK, and we therefore considered the hypothesis that MKP-1 induction may be antiapopto...

MAP kinase phosphatase (MKP)-3 is a cytoplasmic dual specificity protein phosphatase that specifically binds to and inactivates the ERK1/2 MAP kinases in mammalian cells. However, the molecular basis of the cytoplasmic localization of MKP-3 or its physiological significance is unknown. We have used MKP-3-green fluorescent protein fusions in conjunction with leptomycin B to show that the cytopla...

In this study we generated a novel dual specific phosphatase 4 (DUSP4) deletion mouse using a targeted deletion strategy in order to examine the role of MAP kinase phosphatase-2 (MKP-2) in immune responses. Lipopolysaccharide (LPS) induced a rapid, time and concentration-dependent increase in MKP-2 protein expression in bone marrow-derived macrophages from MKP-2(+/+) but not from MKP-2(-/-) mic...

The mitogen-activated protein (MAP) kinase phosphatase 1 (MKP-1) plays a major role in dephosphorylating and thereby inactivating the MAP kinases extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38. Here, we examine the posttranscriptional events underlying the robust MKP-1 induction by oxidants in HeLa cells. H(2)O(2) treatment potently stabilized the MKP-1 mRNA...

The mitogen-activated protein kinase (MAPK) pathway plays a critical role in Toll-like receptor (TLR) signaling. MAPK phosphatase-1 (MKP-1) inhibits the MAPK pathway and decreases TLR signaling, but the regulation of MKP-1 is not completely understood. We now show that MKP-1 is acetylated, and that acetylation regulates its ability to interact with its substrates and deactivate inflammatory sig...

Mitogen-activated protein kinase phosphatase 3 (MKP-3) is a negative regulator of extracellular signal-related kinase signaling. Our laboratory recently demonstrated that MKP-3 plays an important role in obesity-related hyperglycemia by promoting hepatic glucose output. This study shows that MKP-3 deficiency attenuates body weight gain induced by a high-fat diet (HFD) and protects mice from dev...