We have determined that the major mitotic phosphoprotein in chromosomes recognized by the antiphosphoprotein antibody MPM-2 is the 170-kDa isoform of topoisomerase II (topo II), the isoform predominant in proliferating cells. As a prerequisite to making this discovery, it was necessary to develop protocols to protect chromosomal proteins from dephosphorylation during cell extraction and chromos...

OBJECTIVE Proteins that are phosphorylated during apoptosis are commonly precipitated by autoantibodies found in the sera of patients with systemic lupus erythematosus. We sought to determine whether scleroderma autoantigens such as small nucleolar RNPs (snoRNP) also associate with phosphoproteins in response to various cellular stressors. METHODS We screened a panel of monoclonal antibodies ...

To determine the role of protein phosphorylation in neutrophil activation, electropermeabilized cells were treated with vanadate, a phosphatase inhibitor. Micromolar concentrations of vanadate elicited a NADPH-dependent burst of oxygen utilization in permeabilized, but not in intact cells, indicating an intracellular site of action. Stimulation of oxygen consumption by vanadate was reversible, ...

Multitarget compounds that act on a diverse set of regulatory pathways are emerging as a therapeutic approach for a variety of cancers. Toward a more specified use of this approach, we hypothesize that the desired efficacy can be recreated in terms of a particular combination of relatively more specific (i.e., ostensibly single target) compounds. We test this hypothesis for the geldanamycin ana...

Spring viraemia of carp virus (SVCV) is an aetiological agent of a serious disease affecting carp farms in Europe and is a member of the Rhabdoviridae family of viruses. The genome of SVCV codes for five proteins: nucleoprotein (N), phosphoprotein (P), matrix protein (M), glycoprotein (G) and RNA-dependent RNA polymerase (L). RNA-mediated interference (RNAi) by small interfering RNAs (siRNAs) i...

Incubation of Burkitt lymphoma-derived Raji cells at physiological temperature with submicromolar concentrations of humanized anti-CD20 antibody rituximab (RTX) redistributes CD20 to liquid-ordered, plasma membrane rafts. This accumulation of the CD20 tetraspan protein in rafts does not change the existing lipid and phosphoprotein composition but makes sphingolipids and the Src regulator Cbp/PA...

Membrane Associated Guanylate Kinases (MAGUKs) contain a protein interaction domain (GK(dom)) derived from the enzyme Guanylate Kinase (GK(enz)). Here we show that GK(dom) from the MAGUK Discs large (Dlg) is a phosphoprotein recognition domain, specifically recognizing the phosphorylated form of the mitotic spindle orientation protein Partner of Inscuteable (Pins). We determined the structure o...

In the nutrition of the young, the r&e of phosphoproteins is, without doubt, an important one. As casein in milk, or as the yellow yolk of many vertebrate and invertebrate eggs, phosphoprotein occurs in substantial quantities. In the frog egg, for example, the yolk platelets occupy almost half the volume of the cell. According to McClendon (5), the yolk of the frog egg consists of phosphoprotei...

Phosphorylation of rabbit skeletal muscle glycogen synthase by cyclic AMP-independent synthase kinase 1 results in the incorporation of 4 mol of PO4/subunit. Incubation of the phosphorylated synthase with rabbit muscle phosphoprotein phosphatase brings about the hydrolysis of phosphates from all four major tryptic peptides and an increase in the synthase activity ratio from 0.01 to 0.85. Incuba...