Teleost rod photoreceptors elongate in the light and shorten in darkness. We are investigating the role of cAMP-dependent protein kinase (PKA), phosphatases and target phosphoproteins in the regulation of photoreceptor cell shape. Preparations of rod fragments, consisting of the motile inner segment with attached photosensory outer segment (RIS-ROS), undergo light-stimulated elongation in cultu...

Two alkaline phosphatases were extracted from the membranes of Bacillus subtilis 168 stationary-phase cells and purified as homogeneous proteins by hydroxyapatite column chromatography. Alkaline phosphatases I and II differed in several properties such as subunit molecular weight, substrate specificity, thermostability, Km, pH stability, and peptide maps.

A protein phosphatase, designated Pph3, from Myxococcus xanthus showed the enzymatic characteristics of PP2C-type serine/threonine protein phosphatases, which are metal ion-dependent, okadaic acid-insensitive protein phosphatases. The pph3 mutant under starvation conditions formed immature fruiting bodies and reduced sporulation.

Type 2 diabetes is increasing at an alarming rate worldwide, and there has been a considerable effort in several laboratories to identify suitable targets for the design of drugs against the disease. To this end, the protein tyrosine phosphatases that attenuate insulin signaling by dephosphorylating the insulin receptor (IR) have been actively pursued. This is because inhibiting the phosphatase...

The kinetoplastid protozoan parasites belonging to the genus Leishmania are the causative agents of different clinical forms of leishmaniasis, a vector-borne infectious disease with worldwide prevalence. The protective host immune response against Leishmania parasites relies on myeloid cells such as dendritic cells and macrophages in which upon stimulation by cytokines (e.g., interferon-γ) a co...

Endothall, an older commercial herbicide, and cantharidin, a natural product from the blister beetle (Epicauta spp.), are close chemical analogues. A comparison of the effect of endothall and cantharidin on plants revealed a similarity in their level of phytotoxicity on both Arabidopsis thaliana and Lemna paucicostata. Cantharidin is a potent inhibitor of animal serine/threonine protein phospha...

Tissue phosphatases which are present in virus suspensions were found to contribute in considerable measure to the inactivation of herpes simplex virus. Phosphatase inhibitors and phosphatase substrates have been found to prolong the survival of the virus. Exogenous phosphatases, both acid and alkaline, have been demonstrated to bring about the loss of infectivity of suspensions of this virus.

Protein phosphorylation is one of the most important post-translational modifications regulating various signaling processes in all known living organisms. In the cell, protein phosphatases and protein kinases play a dynamic antagonistic role, controlling the phosphorylation state of tyrosine (Tyr), serine (Ser) and threonine (Thr) side chains of proteins. The reversible phosphorylation modulat...