Conditional knockdown of proteasomes results in cell-cycle arrest and enhanced expression of molecular chaperones Hsp70 and Hsp40 in chicken DT40 cells |
| |
Authors: | Tanahashi-Hori Tomoko Tanahashi Nobuyuki Tanaka Keiji Chiba Tomoki |
| |
Affiliation: | Department of Molecular Oncology, The Tokyo Metropolitan Institute of Medical Science, 3-18-22 Honkomagome, Bunkyo-ku, Tokyo 113-8613, Japan. |
| |
Abstract: | The 26 S proteasome is an evolutionarily conserved ATP-dependent protease complex that degrades poly-ubiquitinated proteins and plays essential roles in a critical part of cellular regulation. In vertebrates, the roles of the proteasome have been widely studied by use of specific inhibitors, but not genetically. Here, we generated a cell line Z(-/-/-)/Z-HA, in which the expression of the catalytic subunit of the proteasome, Z (beta2) could be manipulated. This cell line expresses exogenous Z protein under the control of a tetracycline-repressible promoter in a Z-nullizygous genetic background. Treatment of these cells with doxycycline inhibited Z expression and, hence, the function of the proteasome. The latter resulted in accumulation of poly-ubiquitinated proteins and concomitant induction of molecular chaperones Hsp70 and Hsp40. These results suggest a synergistic role for the proteasome with these molecular chaperones to eliminate misfolded or damaged proteins in vivo. Furthermore, knockdown of the proteasome induced apoptotic cell death following cell-cycle arrest at G(2)/M phase. Our Z(-/-/-)/Z-HA cell line would be useful for evaluating proteolytic processes catalyzed by the proteasome in many biological events in vertebrate cells. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|