RBM12

RBM12 is a five-RRM RNA-binding protein that acts as a context-dependent post-transcriptional regulator, controlling target gene expression through direct binding of mRNA features and recruitment of translation machinery (PMID:35622975, PMID:39187545). In erythroid cells it binds preferentially to 5' UTRs of transcripts and suppresses fetal hemoglobin expression, a function that requires its first RRM together with an adjacent linker domain and operates independently of the canonical HbF regulators BCL11A and ZBTB7A/LRF (PMID:35622975). In hepatocellular carcinoma it binds JAK1 mRNA via its fourth RRM and recruits the translation factor EIF4A2 through its second RRM, increasing ribosome loading and JAK1 translation; the resulting JAK1/STAT1 signaling transcriptionally upregulates PD-L1 to drive immune evasion, and RBM12 also promotes HCC proliferation, invasion, and EMT within a miR-497-5p/RBM12/CPNE1 axis (PMID:39187545, PMID:37793588). In neurons and HEK293 cells RBM12 represses the GPCR/cAMP/PKA signaling axis by setting the expression of adenylyl cyclases, phosphodiesterases, and PKA subunits, such that its loss yields hyperactive cAMP production and PKA activity (PMID:37543364). Truncating mutations that remove an RRM segregate with psychosis in familial kindreds and fail to rescue this cAMP/PKA hyperactivity, directly linking RBM12 loss-of-function to psychotic disorder (PMID:28628109, PMID:37543364).

1. 2008 Medium

   Established that RBM12 is transcriptionally coupled to a neighboring gene, raising the possibility of coordinated regulation before any molecular function was known.

   Evidence Comparative genomics and RT-PCR showing shared promoter and 5' exons with CPNE1 across human, mouse, and zebrafish tissues

   PMID:18831769

   Open questions at the time

   • Does not establish any biochemical or RNA-binding function of the RBM12 protein
   • Functional consequence of shared CPNE1 promoter unresolved
2. 2017 Medium

   Answered whether RBM12 has a defined disease role by linking RRM-truncating loss-of-function to a heritable phenotype, motivating mechanistic work.

   Evidence Whole-genome sequencing and family-based genetic analysis of psychosis kindreds identifying nonsense and frameshift mutations

   PMID:28628109

   Open questions at the time

   • No biochemical assay of the protein in this study
   • Molecular pathway through which truncation causes psychosis unidentified
3. 2022 High

   Defined the first molecular activity of RBM12 — sequence-specific mRNA binding to 5' UTRs — and a functional output, suppression of fetal hemoglobin, localizing activity to RRM1 plus a linker.

   Evidence CRISPR screen, depletion, eCLIP-seq, proteome profiling and domain mutagenesis in SCD-derived erythroid cells

   PMID:35622975

   Open questions at the time

   • Mechanism by which 5' UTR binding suppresses HbF (translation vs. stability) not resolved
   • Direct target transcripts driving the phenotype not fully enumerated
4. 2023 High

   Connected RBM12 loss-of-function to a signaling pathway and to the disease variants by showing it represses GPCR/cAMP/PKA signaling and that psychosis-linked truncations cannot rescue.

   Evidence Knockdown in HEK293 and iPSC-derived neurons, cAMP and PKA activity assays, transcriptional reporters, and disease-variant rescue experiments

   PMID:36711667 PMID:37543364

   Open questions at the time

   • Direct mRNA targets among adenylyl cyclase/PDE/PKA effectors not mapped by binding data
   • Whether regulation is via the same 5' UTR-binding mode as in erythroid cells unknown
5. 2023 Medium

   Extended RBM12 to cancer biology, showing pro-tumorigenic activity and placing it in a miRNA-controlled regulatory axis.

   Evidence Proliferation/migration/invasion assays, dual-luciferase validation of miR-497-5p targeting, and CPNE1 downstream analysis in HCC cells

   PMID:37793588

   Open questions at the time

   • Mechanism linking RBM12 to CPNE1 and TGF-β1 secretion not biochemically defined
   • Single-lab functional study
6. 2024 High

   Resolved a direct molecular mechanism by mapping distinct RRMs to mRNA binding and translation-factor recruitment, explaining how RBM12 drives JAK1/STAT1/PD-L1 immune evasion.

   Evidence RNA-binding domain mapping (RRM4 to JAK1 mRNA, RRM2 to EIF4A2), polysome/ribosome profiling, EIF4A2 Co-IP, and JAK1/STAT1 pathway readouts in HCC cells

   PMID:39187545

   Open questions at the time

   • Whether the EIF4A2-recruitment mechanism operates at the 5' UTR targets seen in erythroid and neuronal contexts is untested
   • Structural basis of RRM-specific mRNA and EIF4A2 contacts not determined
7. 2025 Low

   Broadened the disease landscape by associating RBM12 loss-of-function with atherosclerotic vascular disease, though without a mechanism.

   Evidence Exome-wide association study in 434,438 UK Biobank participants

   PMID:41190437

   Open questions at the time

   • No mechanistic experiment performed on RBM12 in vascular tissue
   • Causal pathway linking RBM12 loss to atherosclerosis unknown

• It remains unknown whether RBM12's distinct context-specific outputs (HbF suppression, GPCR/cAMP/PKA repression, JAK1 translational activation) reflect a single unifying biochemical mechanism operating on different targets.
• No unified target map across cell types
• No structural model relating the five RRMs to their respective functions
• Mechanistic basis of atherosclerosis association uncharacterized