title: Interaction between HIV-1 Tat and pRb2/p130: a possible mechanism in the pathogenesis of AIDS-related neoplasms.
abstract: Tat protein is an early nonstructural protein necessary for virus replication, which is secreted by infected cells and taken up by uninfected cells. Extensive evidence indicates that Tat may be a cofactor in the development of AIDS-related neoplasms. The molecular mechanism underlying Tat's oncogenic activity may include deregulation of cellular genes. Among these genes, it has recently been shown that pRb2/p130 oncosuppressor protein is one of the targets in the interaction between HIV gene product Tat and host proteins. However, whether the HIV-1 gene product Tat may inactivate the oncosuppressive function of pRb2/p130 has not yet been elucidated. Here, we show that mRNA levels of pRb2/p130 increase in the presence of Tat, whereas no change in the phosphorylation status of pRb2/p130 is observed. In addition, Tat can inhibit the growth control activity exerted by pRb2/p130 in the T98G cell line. Finally, Tat does not compete with E2F-4 in binding to pRb2/p130. The interaction between Tat and pRb2/p130 seems to result in the deregulation of the control exerted by pRb2/p130 on the cell cycle. Taken together, these results open a window on the role of pRb2/p130 in AIDS-related oncogenesis.
mesh_terms: D002460:Cell Line; D015972:Gene Expression Regulation, Neoplastic; D015967:Gene Expression Regulation, Viral; D015696:Gene Products, tat / Q000378:metabolism*; D015497:HIV-1 / Q000378:metabolism*; D006801:Humans; D016483:Lymphoma, AIDS-Related / Q000209:etiology* / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism*; D011506:Proteins; D016160:Retinoblastoma Protein / Q000378:metabolism*; D050717:Retinoblastoma-Like Protein p130; D014162:Transfection; D054322:tat Gene Products, Human Immunodeficiency Virus
chemical_list: D015696:Gene Products, tat; D010750:Phosphoproteins; D011506:Proteins; C493837:RBL2 protein, human; D016160:Retinoblastoma Protein; D050717:Retinoblastoma-Like Protein p130; D054322:tat Gene Products, Human Immunodeficiency Virus