Expression of nonstructural rotavirus protein NSP4 mimics Ca2+ homeostasis changes induced by rotavirus infection in cultured cells |
| |
| Authors: | Díaz Yuleima Chemello Maria Elena Peña Franshelle Aristimuño Olga Carolina Zambrano Jose Luis Rojas Hector Bartoli Fulvia Salazar Leiria Chwetzoff Serge Sapin Catherine Trugnan Germain Michelangeli Fabian Ruiz Marie Christine |
| |
| Affiliation: | Yuleima Díaz, Maria Elena Chemello, Franshelle Peña, Olga Carolina Aristimuño, Jose Luis Zambrano, Hector Rojas, Fulvia Bartoli, Leiria Salazar, Serge Chwetzoff, Catherine Sapin, Germain Trugnan, Fabian Michelangeli, and Marie Christine Ruiz |
| |
| Abstract: | Rotavirus infection modifies Ca2+ homeostasis, provoking an increase in Ca2+ permeation, the cytoplasmic Ca2+ concentration (Ca2+]cyto), and total Ca2+ pools and a decrease in Ca2+ response to agonists. A glycosylated viral protein(s), NSP4 and/or VP7, may be responsible for these effects. HT29 or Cos-7 cells were infected by the SA11 clone 28 strain, in which VP7 is not glycosylated, or transiently transfected with plasmids coding for NSP4-enhanced green fluorescent protein (EGFP) or NSP4. The permeability of the plasma membrane to Ca2+ and the amount of Ca2+ sequestered in the endoplasmic reticulum released by carbachol or ATP were measured in fura-2-loaded cells at the single-cell level under a fluorescence microscope or in cell suspensions in a fluorimeter. Total cell Ca2+ pools were evaluated as 45Ca2+ uptake. Infection with SA11 clone 28 induced an increase in Ca2+ permeability and 45Ca2+ uptake similar to that found with the normally glycosylated SA11 strain. These effects were inhibited by tunicamycin, indicating that inhibition of glycosylation of a viral protein other than VP7 affects the changes of Ca2+ homeostasis induced by infection. Expression of NSP4-EGFP or NSP4 in transfected cells induced the same changes observed with rotavirus infection, whereas the expression of EGFP or EGFP-VP4 showed the behavior of uninfected and untransfected cells. Increased 45Ca2+ uptake was also observed in cells expressing NSP4-EGFP or NSP4, as evidenced in rotavirus infection. These results indicate that glycosylated NSP4 is primarily responsible for altering the Ca2+ homeostasis of infected cells through an initial increase of cell membrane permeability to Ca2+. |
| |
| Keywords: | |
| 本文献已被 PubMed 等数据库收录！ |
|
