Protein translational machinery is an important component of proteostasis network (PN) that maintains cellular proteostasis and regulates aging and other cellular processes. Ample evidence indicates that inhibition of translation initiation factor activities enhances stress resistance and extends life span in model organisms. Eukaryotic translation initiation factor 5B (eIF5B) is responsible for joining of pre-40S subunits with 60S ribosomal subunits to give a 80S-like complex in protein translational initiation and its silencing may disrupt proteostasis and trigger cellular processes associated with stress responses. In the present work, eIF5B was genetically manipulated in 293T cells. The physiological aspects of eIF5B-knockdown cells (eIF5B-KN) were characterized showing that they grew slower, had a lower level of intracellular reactive oxygen species (ROS), an increased resistance to oxidative stress and an enhanced autophagy. Proteomic analysis showed that silencing of eIF5B resulted in up-regulation of 88 proteins and down-regulation of 130 proteins in eIF5B-KN compared to control cells, which involved in diverse cellular processes including metabolism, RNA processing, and protein metabolism, and DNA synthesis. The autonomous downregulation of the MAPK singnaling pathway was identified that led to the prolonged S-phase cell-cycle arrest and contributed to the slow growth of eIF5B-KN cells. Glutamine transporters were found to be downregulated which enhanced formation of autophagy. Furthermore, eIF5B knockdown compromised the integrity of 28S rRNA and 8.5.8S rRNA that can be rescued via restoring the eIF5B expression level. Taken together, these results demonstrated that eIF5B silencing providesd a negative feedback to down regulate the MAPK signaling pathway which reconstitutesd the proteostasis, resulting in a decrease in cell growth and an enhanced resistance to oxidative stress. Our data provide a useful resource to further biological exploration into functions of protein synthesis in regulation of proteostasis and aging and suggest that eIF5B plays a role in aging process.