Journal
PLANT JOURNAL
Volume 64, Issue 3, Pages 536-550Publisher
WILEY
DOI: 10.1111/j.1365-313X.2010.04347.x
Keywords
eIF5A; RNA binding protein; long-distance trafficking; phloem; translational machinery
Categories
Funding
- USDA CSREES [2006-35304-17346]
Ask authors/readers for more resources
In yeast, eIF5A, in combination with eEF2, functions at the translation step, during the protein elongation cycle. This result is of significance with respect to functioning of the enucleate sieve tube system, as eIF5A was recently detected in Cucurbita maxima (pumpkin) phloem sap. In the present study, we further characterized four CmeIF5A isoforms, encoding three proteins, all of which were present in the phloem sap. Although hypusination of CmeIF5A was not necessary for entry into the sieve elements, this unique post-translational modification was necessary for RNA binding. The two enzymes required for hypusination were detected in pumpkin phloem sap, where presumably this modification takes place. A combination of gel-filtration chromatography and protein overlay assays demonstrated that, as in yeast, CmeIF5A interacts with phloem proteins, like eEF2, known to be involved in protein synthesis. These findings are discussed in terms of a potential role for eIF5A in regulating protein synthesis within the enucleate sieve tube system of the angiosperms.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available