Bovine leukemia virus expression relies on its chromatin organization after integration into the host cell genome. Proviral latency, which results from transcriptional repression in vivo, represents a viral strategy to escape the host immune system and likely allows for tumor progression. Here, we discriminated two types of latency: an easily reactivable latent state of the YR2 provirus and a '...

Cannabinoid receptors negatively regulate adenylate cyclase through a pertussis toxin-sensitive GTP-binding protein. In the present studies, signaling via the adenylate cyclase/cAMP pathway was investigated in the murine thymoma-derived T-cell line, EL4.IL-2. Northern analysis of EL4.IL-2 cells identified the presence of 4-kilobase CB2 but not CB1 receptor-subtype mRNA transcripts. Southern ana...

In the skin, adenosine triphosphate (ATP) is released from various types of cells by environmental stimuli via nonlytic mechanisms, cell damage, or acute death. Because ATP a potent inducer skin inflammation, it has to be promptly hydrolyzed for achieve homeostasis. Of note, activates mast (MCs) through P2X7R, leading enhanced inflammation. However, MC involvement in impairment inflammation hyd...

The kinetic relationship between depletion of endoplasmic reticulum calcium stores and the activation of a calcium release-activated calcium current (Icrac) was investigated in the RBL-1 mast cell line. The inositol trisphosphate receptor activator, inositol 2,4, 5-trisphosphate ((2,4,5)IP3), the sarcoplasmic-endoplasmic reticulum calcium ATPase inhibitor, thapsigargin, and the calcium ionophor...

To explore the role of calcium in mediating the action of carbachol in chloride-secreting epithelia, we simultaneously measured intracellular free [Ca] ([Ca].) and the potassium conductance (gx) of the basolateral membrane in T84 cells grown on collagen-coated filters. [Call was measured with fura-2 and fluores-cence microscopy and expressed as a relative value ([Ca][) normalized to control. To...

Toxoplasma gondii tachyzoites were loaded with the fluorescent indicator fura 2 to investigate the transport mechanisms involved in maintaining their intracellular Ca2+ homoeostasis. The mitochondrial ATPase inhibitor oligomycin and the endoplasmic-reticulum Ca(2+)-ATPase inhibitor thapsigargin increased the intracellular Ca2+ concentration ([Ca2+]i), thus indicating the requirement for ATP and...

Muscle contractions cause numerous disturbances in intracellular homeostasis. This makes it impossible to use contracting muscle to identify which of the many signals generated by contractions are responsible for stimulating mitochondrial biogenesis. One purpose of this study was to evaluate the usefulness of L6 myotubes, which do not contract, for studying mitochondrial biogenesis. A second pu...

The AMP-activated protein kinase (AMPK) is an important regulator of cellular metabolism in response to metabolic stress and to other regulatory signals. AMPK activity is absolutely dependent upon phosphorylation of AMPK Thr-172 in its activation loop by one or more AMPK kinases (AMPKKs). The tumor suppressor kinase, LKB1, is a major AMPKK present in a variety of tissues and cells, but several ...