Sphingosine induces activation of multiple signaling pathways that play critical roles in controlling cell death. However, the precise molecular mechanism of cell death induced by sphingosine remains to be clarified. In this study, we show that sphingosine induces death receptor-independent caspase-8 activation and apoptotic cell death via p38 mitogen-activated protein kinase (MAPK) activation ...

The expression of mitogen-activated protein kinases (MAPKs) and MAPK kinases (MEKs) in rat islets of Langerhans and the involvement of MAPKs in regulated insulin secretion were examined. Two major isoforms of both MEK (45 and 46 kDa) and MAPK (42 and 44 kDa) were detected in rat islets and shown to be localized to insulin-secreting beta cells by detection of their expression in the beta cell li...

The role of mitogen-activated protein kinase (MAPK) in abscisic acid (ABA)-induced antioxidant defense was investigated in leaves of maize (Zea mays) plants. Treatments with ABA or H(2)O(2) induced the activation of a 46-kD MAPK and enhanced the expression of the antioxidant genes CAT1, cAPX, and GR1 and the total activities of the antioxidant enzymes catalase, ascorbate peroxidase, glutathione...

Activation of the mitogen-activated protein kinase (MAPK) cascade recently was discovered to play an important role in synaptic plasticity in area CA1 of rat hippocampus. However, the upstream mechanisms regulating MAPK activity and the downstream effectors of MAPK in the hippocampus are uncharacterized. In the present studies we observed that hippocampal MAPK activation is regulated by both th...

BACKGROUND/AIMS An enriched environment (EE) ameliorates learning and memory impairments induced by chronic cerebral hypoperfusion, and the p38 mitogen-activated protein kinase (p38 MAPK) signaling pathway exerts both beneficial and deleterious effects on the nervous system during the progression of ischemia. METHODS The present study investigated whether p38 MAPK participates in the process ...

Activation of mitogen-activated protein kinase (MAPK) is induced by adding thyrotropin-releasing hormone (TRH) to COS-7 cells cotransfected with TRH receptors and an epitope-tagged MAPK. Long term treatment of the cells with pertussis toxin has no effect on TRH-induced MAPK activation. Incubation of the cells with the protein kinase C (PKC) inhibitor GF109203X causes an almost complete inhibiti...

ERK1 and ERK2 mitogen-activated protein kinases (MAPK) play a critical role in regulation of cell proliferation and differentiation in response to mitogens and other extracellular stimuli. Mitogens and cytokines that activate MAPK in T cells have been shown to activate human immunodeficiency virus type 1 (HIV-1) replication. Little is known about the signal transduction pathways that activate H...

There is relatively little known about expression and activation of p38 mitogen-activated protein kinases (MAPKs) through G protein-linked, seven-transmembrane-spanning (STM) receptors in mammalian smooth muscle. To investigate the role of p38 MAPK in smooth muscle, we cloned and sequenced the p38 MAPK expressed in canine smooth muscles. A full-length clone of the canine p38 MAPK expressed in c...

The fungal kingdom displays an extraordinary diversity of lifestyles, developmental processes, and ecological niches. The MAPK (mitogen-activated protein kinase) cascade consists of interlinked MAPKKK, MAPKK, and MAPK, and collectively such cascades play pivotal roles in cellular regulation in fungi. However, the mechanism by which evolutionarily conserved MAPK cascades regulate diverse output ...