title: Alterations in RNA processing during immune-mediated programmed cell death.
abstract: During immune-mediated death, death-inducing granzyme (Gzm) proteases concentrate in the nucleus of cells targeted for immune elimination, suggesting that nuclear processes are important targets. Here we used differential 2D proteomics of GzmA-treated nuclei to identify potential GzmA substrates. Of 44 candidates, 33 were RNA-binding proteins important in posttranscriptional RNA processing, including 14 heterogeneous nuclear ribonucleoproteins (hnRNP). Multiple hnRNPs were degraded in cells undergoing GzmA-, GzmB-, or caspase-mediated death. GzmA and caspase activation impaired nuclear export of newly synthesized RNA and disrupted pre-mRNA splicing. Expressing GzmA-resistant hnRNP A1 inhibited GzmA-mediated cell death and rescued pre-mRNA splicing, suggesting that hnRNP A1 is an important GzmA substrate. Cellular stresses are known to inhibit initiation of cap-dependent translation. Disrupting pre-mRNA processing should block further new protein synthesis and promote death by interfering with pathways induced to protect cells from death.
authors.affiliation: Immune Disease Institute and Program in Molecular and Cellular Medicine, Children's Hospital Boston, Harvard Medical School, Boston MA 02115, USA.
authors.forename: Danielle K
authors.initials: DK
authors.lastname: Rajani
authors.forename: Michael
authors.initials: M
authors.lastname: Walch
authors.forename: Denis
authors.initials: D
authors.lastname: Martinvalet
authors.forename: Marshall P
authors.initials: MP
authors.lastname: Thomas
authors.forename: Judy
authors.initials: J
authors.lastname: Lieberman
mesh_terms: D017209:Apoptosis; D002460:Cell Line; D002461:Cell Line, Transformed; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism*; D003602:Cytotoxicity, Immunologic; D015180:Electrophoresis, Gel, Two-Dimensional; D015870:Gene Expression; D053804:Granzymes / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B / Q000235:genetics / Q000378:metabolism; D034441:Heterogeneous-Nuclear Ribonucleoproteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D019169:Jurkat Cells; D020014:K562 Cells; D013058:Mass Spectrometry; D008856:Microscopy, Fluorescence; D020543:Proteome / Q000235:genetics / Q000378:metabolism; D040901:Proteomics / Q000379:methods; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013379:Substrate Specificity
chemical_list: D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D020543:Proteome; D012322:RNA Precursors; D053804:Granzymes