RNA-binding factor involved in multiple aspects of cellular processes like alternative splicing of pre-mRNA and translation regulation. Modulates alternative 5'-splice site and exon selection. Acts as a muscle cell differentiation-promoting factor. Activates exon skipping of the PTB pre-mRNA during muscle cell differentiation. Antagonizes the activity of the splicing factor PTBP1 to modulate muscle cell-specific exon selection of alpha tropomyosin. Binds to intronic pyrimidine-rich sequence of the TPM1 and MAPT pre-mRNAs. Required for the translational activation of PER1 mRNA in response to circadian clock. Binds directly to the 3'-UTR of the PER1 mRNA. Exerts a suppressive activity on Cap-dependent translation via binding to CU-rich responsive elements within the 3'UTR of mRNAs, a process increased under stress conditions or during myocytes differentiation. Recruits EIF4A1 to stimulate IRES-dependent translation initiation in respons to cellular stress. Associates to internal ribosome entry segment (IRES) in target mRNA species under stress conditions. Plays a role for miRNA-guided RNA cleavage and translation suppression by promoting association of EIF2C2-containing miRNPs with their cognate target mRNAs. Associates with miRNAs during muscle cell differentiation. Binds preferentially to 5'-CGCGCG[GCA]-3' motif in vitro.
Expressed in the cerebellum. Expressed in neurons and glial cells, including layers II neurons in the frontal cortex and CA1 pyramidal neurons in the hippocampus. Expressed in heart, liver, pancreas, skeletal muscle, placenta, primary fibroblasts and peripheral blood monocytes (at protein level). Ubiquitously expressed. Highly expressed in heart, placenta and skeletal muscle. Weakly expressed in pancreas, kidney, liver, lung and brain.
Found to be expressed in fetal brain. Down-regulated in fetal Down syndrome (DS) brain.
Phosphorylation on Ser-309 is induced upon cell muscle differentiation (By similarity). Phosphorylated. Phosphorylated in vitro on Ser-309 by SRPK1. Phosphorylation on Ser-309 is induced upon cell stress signaling, which alters its subcellular localization and may modulate its activity on IRES-mediated mRNA translation.
Nucleus. Nucleus > nucleolus. Nucleus speckle. Cytoplasm. Cytoplasmic granule. Undergoes continuous nucleocytoplasmic shuttling. Upon nuclear import colocalizes with SR proteins in nuclear speckles. Arsenite stress-induced phosphorylation increases its subcellular relocalization from the nucleus to the cytoplasm and to cytoplasmic stress granules (SG) via a p38 MAPK signaling pathway. Primarily localized in nucleus and nucleoli under cell growth conditions and accumulated in the cytoplasm and cytoplasm perinuclear granules upon muscle cell differentiation.