Cellular uptake and in situ binding of a peptide agonist for calmodulin

We have used the method of inverted hydropathy to develop peptides that int eract with EF hands of calmodulin (CaM). Previously we have shown these pep tides specifically interact with their desired target in a productive manne r, in that they activated CaM in the absence of Ca2+. Therefore, we sought to determine whether these peptides would enter cells, remain intact, and i nteract with CaM in the interior of the cell. Using several techniques we h ave demonstrated cellular uptake, stability, and an intracellular interacti on with CaM with fluorescein-labeled and radiolabeled peptides in Jurkat T cells. The results suggest that these peptides may be useful in the study a nd the manipulation of Ca2+-mediated pathways in cells. (C) 2000 Academic P ress.