Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.16 (calcineurin)
 17,112 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sanguinarine, a plant alkaloid, was identified as a potent and specific protein phosphatase (PP) 2C inhibitor. It inhibited PP2C competitively with respect to alpha-casein (Ki=0.68 microM) and showed selectivity for PP2C as compared with PP1, PP2A, and PP2B in vitro. In vivo, sanguinarine showed cytotoxicity toward human promyelocytic leukemia cell line HL60, with an IC(50) value of 0.37 microM, and induced apoptosis through a caspase-3/7-dependent mechanism involving the phosphorylation of p38, a PP2Calpha substrate. The apoptosis activity induced by sanguinarine was partially inhibited by a p38 inhibitor, SB203580, and was involved in the phospho-p38 protein in HL60 cells.
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PMID:Sanguinarine as a potent and specific inhibitor of protein phosphatase 2C in vitro and induces apoptosis via phosphorylation of p38 in HL60 cells. 2020 61

Aquaporin 2 (AQP2) trafficking is regulated by phosphorylation and dephosphorylation of serine residues in the AQP2 COOH terminus. Vasopressin (VP) binding to its receptor (V2R) leads to a cascade of events that result in phosphorylation of serine 256 (S256), S264, and S269, but dephosphorylation of S261. To identify which phosphatase is responsible for VP-induced S261 dephosphorylation, we pretreated cells with different phosphatase inhibitors before VP stimulation. Sanguinarine, a specific protein phosphatase (PP) 2C inhibitor, but not inhibitors of PP1, PP2A (okadaic acid), or PP2B (cyclosporine), abolished VP-induced S261 dephosphorylation. However, sanguinarine and VP significantly increased phosphorylation of ERK, a kinase that can phosphorylate S261; inhibition of ERK by PD98059 partially decreased baseline S261 phosphorylation. These data support a role of ERK in S261 phosphorylation but suggest that, upon VP treatment, increased phosphatase activity overcomes the increase in ERK activity, resulting in overall dephosphorylation of S261. We also found that sanguinarine abolished VP-induced S261 dephosphorylation in cells expressing mutated AQP2 S256A, suggesting that the phosphorylation state of S261 is independent of S256. Sanguinarine alone did not induce AQP2 membrane trafficking, nor did it inhibit VP-induced AQP2 membrane accumulation in cells and kidney tissues, suggesting that S261 does not play an observable role in acute AQP2 membrane accumulation. In conclusion, PP2C activity is required for S261 AQP2 dephosphorylation upon VP stimulation, which occurs independently of S256 phosphorylation. Understanding the pathways involved in modulating PP2C will help elucidate the role of S261 in cellular events involving AQP2.
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PMID:Protein phosphatase 2C is responsible for VP-induced dephosphorylation of AQP2 serine 261. 2838 58