cAMP-regulated phosphoprotein 21 (ARPP21)

cAMP-regulated phosphoprotein 21 (ARPP21) is a highly conserved RNA-binding phosphoprotein enriched in certain brain regions, notably the striatum and cortex. ARPP21 recognizes uridine-rich sequences in the 3′ untranslated regions of target mRNAs, promoting their translation by interacting with components of the translation initiation complex (particularly eIF4F). This action counterbalances repression by microRNA miR-128, which is encoded within the ARPP21 host gene. ARPP21 plays pivotal roles in neuronal excitability, dendritic branching, and post-transcriptional control of gene expression in neural development. In the thymus, ARPP21 directly binds and promotes Rag1 mRNA translation, enhancing T cell receptor (TCR) repertoire diversity. The protein is subject to regulation by phosphorylation and ubiquitination in response to calcium signaling. Although implicated as a candidate gene for intellectual disability in CNVs and as part of a chemoresistance regulatory network in cancer, ARPP21 is not currently an established druggable target nor used in routine clinical biomarker assays.

Other names

ARPP-21R3HDM3RCSTARPPThymocyte cAMP-regulated phosphoproteinR3H domain containing 3

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