Linked Life Data

19631221

Source:http://linkedlifedata.com/resource/pubmed/id/19631221

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2009-9-21
pubmed:abstractText
The non-ribosomal functions of mammalian ribosomal proteins have recently attracted worldwide attention. The mouse ribosomal protein S5 (rpS5) derived from ribosomal material is an assembled non-phosphorylated protein. The free form of rpS5 protein, however, undergoes phosphorylation. In this study, we have (a) investigated the potential role of phosphorylation in rpS5 protein transport into the nucleus and then into nucleoli and (b) determined which of the domains of rpS5 are involved in this intracellular trafficking. In vitro PCR mutagenesis of mouse rpS5 cDNA, complemented by subsequent cloning and expression of rpS5 truncated recombinant forms, produced in fusion with green fluorescent protein, permitted the investigation of rpS5 intracellular trafficking in HeLa cells using confocal microscopy complemented by Western blot analysis. Our results indicate the following: (a) rpS5 protein enters the nucleus via the region 38-50 aa that forms a random coil as revealed by molecular dynamic simulation. (b) Immunoprecipitation of rpS5 with casein kinase II and immobilized metal affinity chromatography analysis complemented by in vitro kinase assay revealed that phosphorylation of rpS5 seems to be indispensable for its transport from nucleus to nucleoli; upon entering the nucleus, Thr-133 phosphorylation triggers Ser-24 phosphorylation by casein kinase II, thus promoting entrance of rpS5 into the nucleoli. Another important role of rpS5 N-terminal region is proposed to be the regulation of protein's cellular level. The repetitively co-appearance of a satellite C-terminal band below the entire rpS5 at the late stationary phase, and not at the early logarithmic phase, of cell growth suggests a specific degradation balancing probably the unassembled ribosomal protein molecules with those that are efficiently assembled to ribosomal subunits. Overall, these data provide new insights on the structural and functional domains within the rpS5 molecule that contribute to its cellular functions.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
1089-8638
pubmed:author
pubmed:issnType
Electronic
pubmed:day
9
pubmed:volume
392
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1192-204
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
On the intracellular trafficking of mouse S5 ribosomal protein from cytoplasm to nucleoli.
pubmed:affiliation
Laboratory of Biochemistry, School of Chemistry, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece.
pubmed:publicationType
Journal Article