Isoform 2 may participate in the regulation of nucleoplasmic coilin protein interactions in neuronal and transformed cells. Isoform 3 can regulate global protein synthesis by altering nucleolar numbers. Isoform 4 may play a role as a modulator of APP processing. Overexpression can down-regulate APP processing. Isoform 3 interacts with DLG4 (By similarity). Interacts with EPHA8. Isoform 2 interacts with COIL. Isoform 4 interacts with APP and EPHA8. Isoform 6 interacts with EPHA8. The synaptic localization requires DLG4 interaction. Translocation to the nucleus in response to stimulation of NMDA receptors (NMDARs) in a calcium-independent manner (By similarity). The interaction with APP causes its partial exclusion from the nucleus, when APP is overexpressed. Highly expressed in marrow from patients with pre-B ALL associated with the t(1;19) translocation. Strongly expressed in brain and testis. Expressed in fetal brain. Isoform 4 is highly expressed in brain (at protein level). Isoform 6 is expressed in brain and several cancer cell lines. Transcriptionally up-regulated in t(1:19) pre-B cell acute lymphocytic leukemia by the chimeric TCF3-PBX1. Not expressed in pre-B cell that lack this translocation. Isoform 3 nuclear translocation requires an NMDAR-dependent proteolytic cleavage. Truncated N-terminus.