title: Alternative splicing of CARMA2/CARD14 transcripts generates protein variants with differential effect on NF-κB activation and endoplasmic reticulum stress-induced cell death.
abstract: The caspase recruitment domain (CARD)-containing proteins CARMA1-3 share high degree of sequence, structure and functional homology. Whereas CARMA1 and CARMA3 have been identified as crucial components of signal transduction pathways that lead to activation of NF-κB transcription factor, little is known about the function of CARMA2. Here we report the identification of two splice variants of CARMA2. One transcript, named CARMA2short (CARMA2sh), is predicted to encode for a CARMA2 polypeptide containing the CARD, coiled coil, and a PDZ domains, but lacking the SH3 and the GuK domains. The second variant, CARMA2cardless (CARMA2cl), encodes for a polypeptide lacking the CARD domain and containing only a portion of the coiled coil domain and a linker region. Expression analysis confirmed the presence of the CARMA2 alternatively spliced transcripts in both human cell lines and tissues. Fluorescence microscopy data show that both splice variants localize in the cytosol. Biochemical experiments indicate that CARMA2sh interacts with TRAF2 and activates NF-κB in a TRAF2-dependent manner. Finally, CARMA2sh variant protects cells from apoptosis induced by different stimuli. Taken together, these results demonstrate that multiple transcripts encoding several CARMA2 isoforms exist in vivo and regulate NF-κB activation and apoptosis.
authors.affiliation: Biogem, Ariano Irpino, Italy.
authors.forename: Ivan
authors.initials: I
authors.lastname: Scudiero
authors.forename: Tiziana
authors.initials: T
authors.lastname: Zotti
authors.forename: Angela
authors.initials: A
authors.lastname: Ferravante
authors.forename: Mariangela
authors.initials: M
authors.lastname: Vessichelli
authors.forename: Pasquale
authors.initials: P
authors.lastname: Vito
authors.forename: Romania
authors.initials: R
authors.lastname: Stilo
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D053468:CARD Signaling Adaptor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003600:Cytosol / Q000201:enzymology; D004721:Endoplasmic Reticulum / Q000201:enzymology* / Q000473:pathology; D017930:Genes, Reporter; D006162:Guanylate Cyclase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D007527:Isoenzymes; D019169:Jurkat Cells; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism*; D013312:Stress, Physiological; D047992:TNF Receptor-Associated Factor 2 / Q000235:genetics / Q000378:metabolism; D014162:Transfection
chemical_list: D053468:CARD Signaling Adaptor Proteins; D007527:Isoenzymes; D008565:Membrane Proteins; D016328:NF-kappa B; D012333:RNA, Messenger; D047992:TNF Receptor-Associated Factor 2; C426243:CARD14 protein, human; D006162:Guanylate Cyclase