The Role of mRNA Translation Inhibitor Programmed Cell Death 4 (PDCD4) During Differentiation in Skeletal Muscle Cells

PDCD4 is a downstream substrate of mammalian/mechanistic target of rapamycin complex 1/ S6 ribosomal protein kinase 1 (mTORC1/ S6K1) pathway. It is known as an apoptotic protein, a tumour suppressor and an mRNA translation inhibitor. PDCD4 expression at the onset of differentiation was significantly greater than on Day 0, the time of change from growth to differentiation medium (p<0.05). This observation is corresponding to the mRNA expression (p<0.05). Using the pulse-chase technique, PDCD4 degradation rate was significantly different between Day 0 and Day 1 (p<0.05). Taking together, these imply that PDCD4 abundance during the onset of differentiation is likely regulated at the level of both protein synthesis and degradation. siRNA-mediated knockdown of PDCD4 led to a decrease in myogenic protein abundance during differentiation (p<0.05), and overexpression of PDCD4 stimulated differentiation (p<0.05). My study showed that the regulation of PDCD4 level may help in the management of muscle atrophy.