Cloning, characterization and immunolocalization of two subunits of calcineurin from pearl oyster (Pinctada fucata).

Calcineurin (CN), consisting of catalytic subunit (CN A) and regulatory subunit (CN B), is a multifunctional protein involved in many important physiological processes. Here, we cloned two subunits of CN (Pf-CN A and Pf-CN B) from pearl oyster Pinctada fucata and reported, for the first time, its expression patterns in the developmental stages, its enzymatic activity and immunolocalization in various tissues of adult pearl oyster. The Pf-CN A was extensively localized in all the tested tissues including mantle, gonad, digestive gland, gills, adductor muscle, and foot with strong signals detected in gonad, gills, foot, and mantle. Importantly, Pf-CN A was mainly found in the inner epithelial cells of the basal periostracal groove and lateral surface of the inner mantle fold, in which organic macromolecules used for periostracum formation and shell construction are secreted, respectively. In gill, the strong signals were distributed in the epithelial cells of the branchial filaments and the base of gill filaments. All the results suggested that Pf-CN may participate in the development of the pearl oyster and function in many ways in various physiological activities, especially in the shell formation. Our observations could provide some important clues to further understanding of the functions of CN in the oyster.

Changes in calcineurin expression induced in the rat brain by the administration of antipsychotics.

Calcineurin (CN) was recently identified as a susceptibility gene for schizophrenia as well as showing altered RNA expression levels in the post-mortem brains of individuals with schizophrenia. CN knockout mice show a number of behaviours associated with schizophrenia, including deficits in sensorimotor gating, suggesting a link between CN and psychosis. Concurrently, we found, using genome screening techniques, that antipsychotics alter CN expression levels. Therefore, western blotting, in situ hybridization, immunocytochemistry and phosphatase assays were employed to determine what effect antipsychotics have on CN. The results indicate that clozapine, risperidone and haloperidol cause substantial reductions in the A subunit of CN but not CN B at both the RNA and protein levels in the striatum and prefrontal cortex. The changes could only be observed after repeated treatment with antipsychotics but not after acute administration. The alterations in CN protein levels were specific to antipsychotics and mediated by D2 dopamine receptor antagonism. However, despite reductions in CN protein levels, the phosphatase activity of CN was significantly elevated after treatment with antipsychotics. Collectively the results suggest that CN may be a common target for antipsychotics and that antipsychotic-induced alterations in CN may represent one of the mechanisms by which antipsychotics alleviate psychosis.

IP-10, apoptotic genes, and calcineurin subtype messenger RNA kinetics occurring in rat renal isografts from brain-dead donors.

BACKGROUND: Brain death (BD) and following ischemia/reperfusion(I/R) injury has cardinal implications in kidney transplantation (Tx). We hypothesize that inflammation, apoptosis, and drug nephrotoxicity are central mechanisms leading to initial organ damage in transplantation from BD donors. In this study, the gene kinetics of a chemokine (IP-10), an apotosis-related gene, and of calcineurin (Cn) subtype were compared using kidney isografts from BD versus living donors. METHODS: Donors were intubated and mechanically ventilated for 6 hours. Grafts were harvested 6 hours after BD, and at 1, 6, and 24 hours and 5 days after engraftment. Messenger RNA (mRNA) expression was assessed using real-time reverse transcriptase-polymerase chain reaction. RESULTS: Gene expression of IP-10 was up-regulated only among BD donor kidneys, particularly following I/R injury. These changes recovered to baseline levels thereafter. Bcl-2 was suppressed within 6 hours of BD and 1 hour after engraftment. In contrast, Bax in kidneys from BD donors was significantly up-regulated at 6 hours after engraftment. These changes were minimal in the controls. Cn Aalpha and Abeta were decreased in kidneys from BD donors before and within 1 hour after engraftment. However, these differences became insignificant thereafter. CONCLUSIONS: Marked up-regulation of IP-10 may predict the initial graft injury and the onset of delayed graft function. Apoptotic gene changes may lead kidney grafts to a preapoptotic condition and up-regulate renal toxicity caused by Cn inhibitors. This initial antigen-independent donor circumstance may be one risk factor for chronic rejection.

An Arabidopsis SNF1-related protein kinase, AtSR1, interacts with a calcium-binding protein, AtCBL2, of which transcripts respond to light.

AtSR1 is a protein kinase of Arabidopsis thaliana, which belongs to the SNF1-related protein kinase subfamily 3. We previously showed accumulation of its transcripts to be responsive to light. In this study, we examined the interaction between AtSR1 and six calcineurin B like proteins of Arabidopsis and found that AtSR1 prominently interacts with one of them, AtCBL2, by yeast two-hybrid assay. Interaction between AtSR1 and AtCBL2 could also be directly confirmed in vitro by pull down assay. RNA blot and reverse transcription-polymerase chain reaction analyses showed that transcripts of AtCBL2, and also of AtCBL1, another CBL, increased upon illumination of leaves. The physiological meaning of the interaction of AtSR1and AtCBL2 is not clear, but they presumably function in signal transduction of light.