The effects of various polycation-stimulated (PCS) phosphatases and of the active catalytic subunit of the ATPMg-dependent (AMDc) protein phosphatase on the activity of casein kinase 2 (CK-2) were investigated by using the synthetic peptide substrate Ser-Glu-Glu-Glu-Glu-Glu, whose phosphorylated derivative is entirely insensitive to these protein phosphatases. Previous dephosphorylation of nati...

The electrophoretic pattern (in polyacrylamide gel) for acid phosphatases in the prostate gland was compared with that for other tissues. lsoenzyme 2 predominates in the prostate. The isoenzyme was isolated from the prostate and its biochemical properties were compared with those of acid phosphatases isolated from spleen. lsoenzyme 2 has a molecular weight of about 100,000. Its optimum pH is be...

AIM We hypothesized that the anticancer activity of cannabinoids was linked to induction of phosphatases. MATERIALS AND METHODS The effects of cannabidiol (CBD) and the synthetic cannabinoid WIN-55,212 (WIN) on LNCaP (prostate) and SW480 (colon) cancer cell proliferation were determined by cell counting; apoptosis was determined by cleavage of poly(ADP)ribose polymerase (PARP) and caspase-3 (...

The level of phosphorylation of any protein depends on the relative activities of protein kinases and protein phosphatases (I), but the latter enzymes have received far less attention, perhaps because of the difficulty in obtaining a well defined substrate before they can be studied. Nevertheless, information about, protein serine/threonine phosphatases has increased enormously over the past fe...

Almost all eukaryotic proteins are subject to post-translational modifications during mitosis and cell cycle, and in particular, reversible phosphorylation being a key event. The recent use of high-throughput experimental analyses has revealed that more than 70% of all eukaryotic proteins are regulated by phosphorylation; however, the mechanism of dephosphorylation, counteracting phosphorylatio...

Preamble Phosphatases constitute a wide class of enzymes which remove a phosphate group from the target substrate by hydrolysing phosphoric acid monoesters into a phosphate ion and a molecule with a free hydroxyl group. This action is directly opposite to that of phosphorylases and kinases. While kinases phosphorylate cellular substrates by using energetic molecules like ATP, phosphatases, in t...

Protein phosphorylation plays a cardinal role in regulating cellular processes in eukaryotes. Phosphorylation of proteins is controlled by protein kinases and phosphatases. We previously reported the light-dependent phosphorylation of the Drosophila transient receptor potential (TRP) ion channel at multiple sites. TRP generates the receptor potential upon stimulation of the photoreceptor cell b...

In rabbit skeletal muscle the polycation-stimulated (PCS) protein phosphatases [Merlevede (1985) Adv. Protein Phosphatases 1, 1-18] are the only phosphatases displaying significant activity toward the deinhibitor protein. Among them, the PCSH protein phosphatase represents more than 80% of the measurable deinhibitor phosphatase activity associated with the PCS phosphatases. The deinhibitor phos...

Posttranslational modification of proteins by phosphorylation is a universal mechanism for regulating diverse biological functions. Recognition that many cellular proteins are reversibly phosphorylated in response to external stimuli or intracellular signals has generated an ongoing interest in identifying and characterizing plant protein kinases and protein phosphatases that modulate the phosp...

1. The characteristics of Ca2+-activated ATPase activities previously often postulated as components for the calcium transporting system in fish gills do not fulfil the requirements of a transport Ca: '-ATPase. 2. The chelation of Ca;~or Mg:~-ions is a prerequisite for the adenosinephosphate esters to serve as substrate for gill plasma membrane phosphatases. 3. Ca2+-activated ATP hydrolysis res...