The kinetics of synthesis and degradation of the protein constituents of nuclear membranes, endoplasmic reticulum membranes (rough-surfaced microsomes), G o 1 g i apparatus membranes and plasma membranes were determined following a single administration of L-[guanido-14C] arginine by intraperitoneal injection. Membrane protein was determined as the fraction which resists sonication and sequenti...

Cancer cells survive and grow despite various advanced anti-cancer therapy. To overcome this antineoplastic resistance, adjuvant therapy is often required to prevent cancer cells' immunoescape capacity. Established tumors build a stressful hostile microenvironment in order escape protective innate adaptive immune responses. Specific conditions factors within tumors, including hypoxia, nutrient ...

Golgi apparatus fractions from rat liver contained all glycosyltransferases which catalyze the in vitro biosynthesis of N-acetylneuraminylgalactosylglucosylceramide (G&, (Nacetylneuraminyl)2-galactosylglucosylceramide (GD3), N-acetylgalactosaminyl(Nacetylneuraminyl) galactosylglucosylceramide (GMz), galactosyl-N-acetylgalactosaminyl-(N-acetylneuraminyl)-galactosylglucosylceramide (GM& and Nacet...

The classical secretion of soluble proteins and transport of integral membrane proteins to the cell surface require transit into and through the endoplasmic reticulum and the Golgi apparatus. Signal peptides or transmembrane domains target proteins for translocation into the lumen or insertion into the membrane of the endoplasmic reticulum, respectively. Here we discuss two mechanisms of unconv...

The effects of hypophysectomy and prolactin administration on the ultrastructure of rat pinealocytes were studied by means of morphometric analysis. Hypophysectomy resulted in an increase in the Golgi apparatus and dense-core vesicles and a decrease in the granular endoplasmic reticulum, lysosomes and lipid droplets. Prolactin administration induced an increase in the granular endoplasmic retic...

The origin of protein bodies in maize (Zea mays L.) endosperm was investigated to determine whether they are formed as highly differentiated organelles or as protein deposits within the rough endoplasmic reticulum. Electron microscopy of developing maize endosperm cells showed that membranes surrounding protein bodies were continuous with rough endoplasmic reticulum membranes. Membranes of prot...

Inositol trisphosphate and cyclic ADP-ribose release Ca2+ from the endoplasmic reticulum via inositol trisphosphate and ryanodine receptors, respectively. By contrast, nicotinic acid adenine dinucleotide phosphate may activate a novel Ca2+ channel in an acid compartment. We show, in two-photon permeabilized pancreatic acinar cells, that the three messengers tested could each release Ca2+ from t...

HER2/Neu/ERBB2 is a receptor tyrosine kinase overexpressed in approximately 20% of human breast tumors. Truncated or mutant isoforms that show increased oncogenicity compared with the wild-type receptor are found in many breast tumors. Here, we report that constitutively active ERBB2 sensitizes human breast epithelial cells to agents that induce endoplasmic reticulum stress, altering the unfold...