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Apoptotic Cleavage of Rabaptin-5-like Proteins and a Model for Rabaptin-5 Inactivation in Apoptosis
Elena V. Korobko, Irina V. Palgova, Sergey L. Kiselev and Igor V. Korobko
volume 5 | issue 16
15 august 2006Pages: 1854 - 1858
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Intracellular membrane transport from the plasma membrane is one of the processes affected in apoptotic cells. Apoptotic inhibition of endosomal transport occurs due to cleavage of Rabaptin-5, an effector of small GTPase Rab5, which results in inhibition of early endosome fusion. Recently several novel Rabaptin-5-like proteins were identified. We investigated whether Rabaptin-5-like proteins, Rabaptin-5? and Rabaptin-5?, are also cleaved in apoptosis and found that both proteins are cleaved in apoptotic cell extracts by caspase-3-related proteases. This suggests that functional inactivation of these proteins is necessary for apoptotic cell death. We also mapped a novel, N-terminal, putative Rab5 binding site in Rabaptin-5-like proteins, which becomes physically separated from the previously known C-terminal Rab5 binding site after apoptotic cleavage of these proteins. Presence of the second Rab5 binding site provides a new insight into Rabaptin-5 function in early endosome fusion and a mechanistic model for functional inactivation of Rabaptin-5 in apoptosis.
We now provide open access to journal articles published online for one year or more. This article may be downloaded at the following link:
Download PDF If the document does not open, please right-click on the link (control-click on a Macintosh) and select the option to save the file to disk.