Article

Plant Molecular Biology

, Volume 57, Issue 4, pp 577-591

First online:

High heterogeneity within the ribosomal proteins of the Arabidopsis thaliana 80S ribosome

  • Patrick GiavaliscoAffiliated withMax-Planck-Institute for Molecular GeneticsInstitute for Human Genetics, Humboldt University BerlinBoyce Thompson Institute for Plant Research
  • , Daniel WilsonAffiliated withMax-Planck-Institute for Molecular Genetics
  • , Thomas KreitlerAffiliated withMax-Planck-Institute for Molecular Genetics
  • , Hans LehrachAffiliated withMax-Planck-Institute for Molecular Genetics
  • , Joachim KloseAffiliated withInstitute for Human Genetics, Humboldt University Berlin
  • , Johan GobomAffiliated withMax-Planck-Institute for Molecular Genetics Email author 
  • , Paola FuciniAffiliated withMax-Planck-Institute for Molecular Genetics Email author 

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Abstract

Proteomic studies have addressed the composition of plant chloroplast ribosomes and 70S ribosomes from the unicellular organism Chlamydomonas reinhardtii But comprehensive characterization of cytoplasmic 80S ribosomes from higher plants has been lacking. We have used two-dimensional gel electrophoresis (2-DE) and mass spectrometry (MS) to analyse the cytoplasmic 80S ribosomes from the model flowering plant Arabidopsis thaliana. Of the 80 ribosomal protein families predicted to comprise the cytoplasmic 80S ribosome, we have confirmed the presence of 61; specifically, 27 (84%) of the small 40S subunit and 34 (71%) of the large 60S subunit. Nearly half (45%) of the ribosomal proteins identified are represented by two or more distinct spots in the 2-DE gel indicating that these proteins are either post-translationally modified or present as different isoforms. Consistently, MS-based protein identification revealed that at least one-third (34%) of the identified ribosomal protein families showed expression of two or more family members. In addition, we have identified a number of non-ribosomal proteins that co-migrate with the plant 80S ribosomes during gradient centrifugation suggesting their possible association with the 80S ribosomes. Among them, RACK1 has recently been proposed to be a ribosome-associated protein that promotes efficient translation in yeast. The study, thus provides the basis for further investigation into the function of the other identified non-ribosomal proteins as well as the biological meaning of the various ribosomal protein isoforms.

Keywords

Arabidopsis thaliana Mass spectrometry Post-translational modification Proteosome RACK1 Ribosome