RNA-binding protein involved in the regulation of alternativepre-RNA splicing and mRNA translation by binding to uridine-rich (U-rich) RNA sequences. Binds to U-rich sequences immediately downstream froma 5' splice sites in a uridine-rich small nuclear ribonucleoprotein (UsnRNP) -dependent fashion, thereby modulating alternative pre-RNAsplicing. Preferably binds to the U-rich IAS1 sequence in a U1 snRNP-dependent manner; this binding isoptimal if a 5' splice site is adjacent to IAS1. Activates the use of heterologous 5' splice sites; the activationdepends on the intron sequence downstream from the 5' splice site, witha preference for a downstream U-rich sequence. Byinteracting with SNRPC/U1-C, promotes recruitment and binding ofspliceosomal U1 snRNP to 5' splice sites followed by U-rich sequences, thereby facilitating atypical 5' splice site recognition by U1 snRNP. Activates splicingof alternative exons with weak 5' splice sites followed by a U-richstretch on its own pre-mRNA and on TIAR mRNA. Acts as amodulator of alternative splicing for the apoptotic FAS receptor, thereby promoting apoptosis. Binds to the 5' splice site region of FAS intron 5 topromote accumulation of transcripts that include exon 6 at the expenseof transcripts in which exon 6 is skipped, thereby leading to thetranscription of a membrane-bound apoptotic FAS receptor, whichpromotes apoptosis. Binds to a conserved AU-rich cis element in COL2A1 intron 2 andmodulates alternative splicing of COL2A1 exon 2. Alsobinds to the equivalent AT-rich element in COL2A1 genomic DNA, and maythereby be involved in the regulation of transcription. Binds specifically to a polypyrimidine-richcontrolling element (PCE) located between the weak 5' splice site andthe intronic splicing silencer of CFTR mRNA to promote exon 9inclusion, thereby antagonizing PTB1 and its role in exon skipping ofCFTR exon 9. Involved in the repression of mRNAtranslation by binding to AU-rich elements (AREs) located in mRNA 3'untranslated regions (3' UTRs), including target ARE-bearing mRNAsencoding TNF and PTGS2. Also participates in thecellular response to environmental stress, by acting downstream of thestress-induced phosphorylation of EIF2S1/EIF2A to promote therecruitment of untranslated mRNAs to cytoplasmic stress granules (SGs), leading to stress-induced translational arrest. Formation and recruitment to SGs is regulated by Zn (2+). Possesses nucleolytic activity against cytotoxiclymphocyte target cells. [1-4]

MEDEMPKTLYVGNLSRDVTEALILQLFSQIGPCKNCKMIMDTAGNDPYCFVEFHEHRHAAAALAAMNGRKIMGKEVKVNWATTPSSQKKDTSSSTVVSTQRSQDHFHVFVGDLSPEITTEDIKAAFAPFGRISDARVVKDMATGKSKGYGFVSFFNKWDAENAIQQMGGQWLGGRQIRTNWATRKPPAPKSTYESNTKQLSYDEVVNQSSPSNCTVYCGGVTSGLTEQLMRQTFSPFGQIMEIRVFPDKGYSFVRFNSHESAAHAIVSVNGTTIEGHVVKCYWGKETLDMINPVQQQNQIGYPQPYGQWGQWYGNAQQIGQYMPNGWQVPAYGMYGQAWNQQGFNQTQSSAPWMGPNYGVQPPQGQNGSMLPNQPSGYRVAGYETQ