The combinatorial PP1-binding consensus Motif (R/K)x( (0,1))V/IxFxx(R/K)x(R/K) is a new apoptotic signature.
BACKGROUND
Previous studies established that PP1 is a target for Bcl-2 proteins and an important regulator of apoptosis. The two distinct functional PP1 consensus docking motifs, R/Kx((0,1))V/IxF and FxxR/KxR/K, involved in PP1 binding and cell death were previously characterized in the BH1 and BH3 domains of some Bcl-2 proteins.


RESULTS
In this study, we demonstrate that DPT-AIF(1), a peptide containing the AIF(562-571) sequence located in a c-terminal domain of AIF, is a new PP1 interacting and cell penetrating molecule. We also showed that DPT-AIF(1) provoked apoptosis in several human cell lines. Furthermore, DPT-APAF(1) a bi-partite cell penetrating peptide containing APAF-1(122-131), a non penetrating sequence from APAF-1 protein, linked to our previously described DPT-sh1 peptide shuttle, is also a PP1-interacting death molecule. Both AIF(562-571) and APAF-1(122-131) sequences contain a common R/Kx((0,1))V/IxFxxR/KxR/K motif, shared by several proteins involved in control of cell survival pathways. This motif combines the two distinct PP1c consensus docking motifs initially identified in some Bcl-2 proteins. Interestingly DPT-AIF(2) and DPT-APAF(2) that carry a F to A mutation within this combinatorial motif, no longer exhibited any PP1c binding or apoptotic effects. Moreover the F to A mutation in DPT-AIF(2) also suppressed cell penetration.


CONCLUSIONS
These results indicate that the combinatorial PP1c docking motif R/Kx((0,1))V/IxFxxR/KxR/K, deduced from AIF(562-571) and APAF-1(122-131) sequences, is a new PP1c-dependent Apoptotic Signature. This motif is also a new tool for drug design that could be used to characterize potential anti-tumour molecules.
Godet
Angélique N
AN
Laboratoire E3 Phosphatases, Unité Signalisation Moléculaire et Activation Cellulaire, Institut Pasteur, Paris, France.
Guergnon
Julien
J
Maire
Virginie
V
Croset
Amélie
A
Garcia
Alphonse
A
D020816:Amino Acid Motifs; D017209:Apoptosis; D001665:Binding Sites; D002463:Cell Membrane Permeability; D002478:Cells, Cultured; D006801:Humans; D020125:Mutation, Missense; D009842:Oligopeptides; D011485:Protein Binding; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D017476:Receptors, Neuropeptide Y / Q000235:genetics* / Q000502:physiology*
D009842:Oligopeptides; D019253:Proto-Oncogene Proteins c-bcl-2; D017476:Receptors, Neuropeptide Y; C109491:neuropeptide Y4 receptor