CaMK phosphatase (CaMKP/POPX2/PPM1F) inhibitors suppress the migration of human breast cancer MDA-MB-231 cells with loss of polarized morphology.

CaMK phosphatase (CaMKP/POPX2/PPM1F) is a Ser/Thr protein phosphatase that belongs to the PPM family. Accumulating evidence suggests that CaMKP is involved in the pathogenesis of various diseases, including cancer. To clarify the relationship between CaMKP activity and human breast cancer cell motility, we examined the phosphatase activity of CaMKP in cell extracts.

CaM kinase phosphatase (CaMKP/PPM1F/POPX2) is specifically inactivated through gallate-mediated protein carbonylation.

CaMK phosphatase (CaMKP/PPM1F/POPX2) is a Mn-dependent, calyculin A/okadaic acid-insensitive Ser/Thr protein phosphatase that belongs to the PPM family. CaMKP is thought to be involved in regulation of not only various protein kinases, such as CaM kinases and p21-activated protein kinase, but also of cellular proteins regulated by phosphorylation. A large-scale screening of a chemical library identified gallic acid and some of its alkyl esters as novel CaMKP inhibitors highly specific to CaMKP.

Effect of heterocyclic pyrimidine compounds on UVB-induced cell damage in human keratinocytes and on melanogenesis in mouse B16 cells.

We investigated the protective effect of several heterocyclic pyrimidine compounds against ultraviolet B (UVB)-induced damage in human keratinocyte HaCaT cells, as well as the inhibitory effect on melanogenesis in B16 melanoma cells. One of the compounds examined, 2-piperadino-6-methyl-5-oxo-5,6-dihydro(7H)pyrrolo[3,4d]pyrimidine maleate (MS-818), showed low cytotoxicity even at 500 microM. At 50-500 microM, MS-818 dose-dependently suppressed the UVB (100 mJ/cm(2))-induced elevation of tumor necrosis factor alpha (TNF-alpha), one of the trigger cytokines for cell death, in HaCaT cells.