High impact information on Calyculin

• Treatment of HepG2 cells with the phosphatase 1 and 2A inhibitors, okadaic acid (> or = 50 nmol/L) and calyculin (> or = 25 nmol/L), decreased IFN-gamma's ability to upregulated C1 INH mRNA [1].
• The WT and G2A enzymes displayed significant differences in the phosphorylation state of Ser617, Ser635, and Ser1179, and mutating all three sites to alanine or restoring phosphorylation with the phosphatase inhibitor calyculin abolished the differences in activity [2].
• Treatment of endothelial cells with calyculin selectively blocks PKA-mediated dephosphorylation of Thr-495 whereas okadaic acid selectively blocks PKC-mediated dephosphorylation of Ser-1177 [3].
• Finally, the stimulation of superoxide production observed in response to CD32 cross-linking was enhanced in calyculin-treated cells [4].
• Inhibition of protein phosphatase-1 by clavosines A and B. Novel members of the calyculin family of toxins [5].

Biological context of Calyculin

• Incubation of cells expressing DRNLS with the phosphatase inhibitor calyculin resulted in the rapid phosphorylation and ubiquitination of DRNLS, suggesting that a nuclear kinase is required to trigger receptor proteolysis [6].
• A series of analogues of okadaic acid and a structurally-distinct PP inhibitor, calyculin, were also found to inhibit the IgE-induced release of mediators from HLMC with the following rank order of potency; calyculin (approximate IC50; 0.015 microM) > okadaic acid (0.2 microM) > okadaol (3.3 microM) > nor-okadaone (> 10 microM) [7].
• Site-directed mutagenesis was used to investigate the mechanism of interaction between the catalytic subunit of human protein phosphatase-1 (PP-1cgamma) and members of the calyculin family of toxins [5].
• The phosphatase inhibitor calyculin antagonizes the rapid initiation of apoptosis by photodynamic therapy [8].
• The time required for calyculin to activate cotransport was longer in swollen cells than in normal cells, indicating that the phosphorylation step is affected by cell volume [9].

Anatomical context of Calyculin

• Basal phosphorylation occurred in the absence of exogenous treatments, and the phosphorylation level was rapidly increased when synaptosomes were treated with the phosphatase inhibitors okadaic acid or calyculin [10].
• After a longer incubation (>5 min) with calyculin, concomitant with an accumulation of serine and threonine phosphorylation, neutrophil responses to CD32 cross-linking were selectively altered [4].
• Reversible phosphorylation as a controlling factor for sustaining calcium oscillations in HeLa cells: Involvement of calmodulin-dependent kinase II and a calyculin A-inhibitable phosphatase [11].
• However, vascular smooth muscles that had been precontracted with the phosphatase inhibitor calyculin were refractory to relaxation [12].
• The concentration required to inhibit by 50% (IC50) the release of histamine was 15 (HLMC) and 50 nM (basophils) for calyculin and 200 (HLMC) and 300 nM (basophils) for okadaic acid [13].

Associations of Calyculin with other chemical compounds

• Tyrosine phosphorylation of Cbl in response to CD32 cross-linking was inhibited by calyculin, and this inhibition was linked with a slower electrophoretic mobility of Cbl as a consequence of its phosphorylation on serine/threonine residues [4].
• 4. Staurosporine, PP1 and the removal of Mg2+ all prevented subsequent stimulation by calyculin A, and all inhibited calyculin-stimulated transport by 20-30 % [14].
• PP7 was resistant to okadaic acid, calyculin and fumonisin B1, and was stimulated by Mn2+ or Fe2+, while Ni2+ and Zn2+ were inhibitory [15].
• Okadaic acid or calyculin, inhibitors of protein phosphatase 1 (PP1) and protein phosphatase 2A (PP2A), augmented the Ba(2+) current [16].
• Swinhoeiamide A, a new highly active calyculin derivative from the marine sponge Theonella swinhoei [17].

Gene context of Calyculin

• Additionally, the phosphatase inhibitors okadaic acid and calyculin enhanced cytokine induction of HO-1 [18].
• Use of the phosphatase inhibitors calyculin and okadaic acid indicated that inhibition of protein phosphatases 1 and 2A dramatically enhanced ERK2 phosphorylation by mGluR1/5 [19].
• Calyculin and okadaic acid promote perilipin phosphorylation and increase lipolysis in primary rat adipocytes [20].
• Different from a considerable translocation of HSL upon PKA activation with isoproterenol, calyculin does not alter HSL redistribution in primary or differentiated adipocytes, as confirmed by both immunostaining and immunoblotting [20].
• Inhibitors of the serine/threonine protein phosphatases PP1 and PP2A, okadaic acid and calyculin induce LT alpha mRNA expression [21].

References