Concomitant transitory up-regulation of X-linked inhibitor of apoptosis protein (XIAP) and the heterogeneous nuclear ribonucleoprotein C1-C2 in surviving cells during neuronal apoptosis.
Although cap-dependent translation initiation is the prevalent mode of ribosome binding to mRNAs in eukaryotes, some mRNAs exhibit the ability to bypass the requirement for the cap structure. The translation of X-chromosome-linked inhibitor of apoptosis protein (XIAP) mRNA is controlled by an internal ribosome entry site (IRES) element, which requires the interaction of the heterogeneous nuclear ribonucleoprotein C1-C2 (hnRNP-C1/C2). We analyze, at the protein level, the time course and distribution of XIAP and hnRNP-C1/C2 upon ischemia in mice or staurosporine (STP)-induced apoptosis in HT22 cells. Both ischemia and STP induced a parallel upregulation of XIAP and hnRNP-C1/C2 protein levels in the penumbra and in HT22 cells. These results suggest that the increased levels of hnRNP C1/C2 may modulate XIAP translation, probably by interacting with the XIAP-IRES. The up-regulation of hnRNP-C1/C2 may foster the synthesis of XIAP as a protective pathway by which neurons try to counteract the initial deleterious effects of apoptosis.
Spahn
A
A
Institute of Cellular and Molecular Anatomy (Anatomie III), Clinic of Johann Wolfgang von Goethe-University, Theodor-Stern-Kai 7, 60590, Franfurt/Main, Germany.
Blondeau
N
N
Heurteaux
C
C
Dehghani
F
F
Rami
A
A
D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D002545:Brain Ischemia / Q000378:metabolism; D053148:Caspase 3 / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival; D045304:Cytochromes c / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000378:metabolism; D005786:Gene Expression Regulation; D034482:Heterogeneous-Nuclear Ribonucleoprotein Group C / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D019311:Staurosporine / Q000378:metabolism; D051636:X-Linked Inhibitor of Apoptosis Protein / Q000235:genetics / Q000378:metabolism*
D004791:Enzyme Inhibitors; D034482:Heterogeneous-Nuclear Ribonucleoprotein Group C; D051636:X-Linked Inhibitor of Apoptosis Protein; D045304:Cytochromes c; D053148:Caspase 3; D019311:Staurosporine