title: Exposure of an arginine-rich protein at surface of cells in S, G2, and M phases of the cell cycle.
abstract: Phenylglyoxal (PG) is shown to be a cell surface probe specific for arginine moieties in protein: (1) It does not enter the cell as evidenced by lack of PG in the cytoplasm. (2) It does not cause excessive cell leakage as measured by release of 51Cr. (3) It reacts with positively-charged groups in proteins at the cell surface but not with those of phospholipids at the surface; since pronase removes PG from the surface, but phospholipase C does not. (4) Under the conditions used in these experiments, it reacts virtually exclusively with arginine moieties in protein (Freedman et al., '68; Takahashi, '68; Werber and Sokolovsky, '72). Synchronized cells were exposed to radioactive PG to assess quantity of arginine moieties in protein at the surface. There is a sharp decrease in arginine at the cell surface at entry into G1 phase from M and a 24-fold increase upon entry into S phase. There is a slight drop in exposed arginine in late S phase followed by an increase to 26 times the G1 level immediately prior to mitosis. Lactoperoxidase-catalyzed iodination of tyrosine moieties in protein at the surface of synchronized cells shows a very gradual increase in protein as the cells move through the cycle and increase in size. Since the increase in arginine moieties in protein at the surface does not reflect a similar increase in total protein at the surface, an arginine-rich protein appears to be exposed at the cell surface during the division-related phases of the cell cycle.
mesh_terms: D001120:Arginine / Q000032:analysis*; D001345:Autoradiography; D002250:Carbon Radioisotopes; D002455:Cell Division; D002462:Cell Membrane / Q000032:analysis; D002860:Chromium Radioisotopes; D003593:Cytoplasm / Q000378:metabolism; D006037:Glyoxal / Q000031:analogs & derivatives / Q000378:metabolism; D006367:HeLa Cells / Q000032:analysis* / Q000378:metabolism; D006801:Humans; D009363:Neoplasm Proteins / Q000032:analysis*; D010740:Phospholipases / Q000378:metabolism; D011402:Pronase / Q000378:metabolism
chemical_list: D002250:Carbon Radioisotopes; D002860:Chromium Radioisotopes; D009363:Neoplasm Proteins; D006037:Glyoxal; D001120:Arginine; D010740:Phospholipases; D011402:Pronase