Phosphorylation of elongation factor-2 from the lepidopteran insect, Spodoptera frugiperda.

In mammalian cells, protein synthesis can be regulated at the level of elongation by the phosphorylation of elongation factor 2 (eEF-2) by a highly specific Ca2+/calmodulin-dependent kinase. In this report, we show that eEF-2 from a cell line derived from the insect, Spodoptera frugiperda, is a substrate for mammalian eEF-2 kinase and that phosphorylation is Ca(2+)-dependent. Furthermore, two-dimensional peptide mapping shows that the kinase phosphorylates the same sites in Spodoptera eEF-2 as those phosphorylated in the rabbit protein. However, we were unable to detect an eEF-2 kinase in Spodoptera cells.