Functional characterization of ribosomal P1/P2 proteins in human cells.
The 'stalk' is a large ribosomal subunit domain that regulates translation. In the present study the role of the ribosomal stalk P proteins in modulating ribosomal activity has been investigated in human cells using RNA interference. A strong down-regulation of P2 mRNA and a drastic decrease in P2 protein in a stable human cell line was achieved using a doxycycline-inducible system. Interestingly, the amount of P1 protein was similarly decreased in these cells, in contrast with the expression of P1 mRNA. The loss of P1/P2 proteins produced a decrease in the growth rate of these cells, as well as an altered polysome pattern with reduced translation efficiency, but without affecting the free 40 S/60 S subunit ratio. A decrease in the ribosomal-subunit joining capacity was also observed. These data indicate that P1/P2 proteins modulate cytoplasmic translation by influencing the interaction between subunits, thereby regulating the rate of cell proliferation.
Martinez-Azorin
Francisco
F
Centro de Biología Molecular 'Severo Ochoa', CSIC (Consejo Superior de Investigaciones Científicas) and UAM (Universidad Autónoma de Madrid), Cantoblanco, E-28049 Madrid, Spain. fmartinez@cbm.uam.es
Remacha
Miguel
M
Ballesta
Juan P G
JP
D015153:Blotting, Western; D002453:Cell Cycle / Q000235:genetics / Q000502:physiology; D002460:Cell Line; D049109:Cell Proliferation; D002470:Cell Survival / Q000235:genetics / Q000502:physiology; D006801:Humans; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D011485:Protein Binding; D014176:Protein Biosynthesis; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012269:Ribosomal Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
D010750:Phosphoproteins; D012333:RNA, Messenger; D012269:Ribosomal Proteins; C031937:phosphoprotein P2, ribosomal