HNRNPM (Heterogeneous Nuclear Ribonucleoprotein M) is an RNA-binding protein that plays essential roles in pre-mRNA processing, mRNA splicing, and translational regulation. The protein is encoded by the HNRNPM gene on chromosome 19p13.3 and belongs to the heterogeneous nuclear ribonucleoprotein (hnRNP) family, a group of proteins that associate with nascent pre-mRNAs in the nucleus. HNRNPM contains multiple RNA recognition motifs (RRMs) that enable it to bind specific RNA sequences and regulate post-transcriptional gene expression.
HNRNPM (Heterogeneous Nuclear Ribonucleoprotein M) is an RNA-binding protein that plays essential roles in pre-mRNA processing, mRNA splicing, and translational regulation. The protein is encoded by the HNRNPM gene on chromosome 19p13.3 and belongs to the heterogeneous nuclear ribonucleoprotein (hnRNP) family, a group of proteins that associate with nascent pre-mRNAs in the nucleus. HNRNPM contains multiple RNA recognition motifs (RRMs) that enable it to bind specific RNA sequences and regulate post-transcriptional gene expression.
The 730-amino acid protein is involved in alternative splicing decisions, mRNA stability, and translation efficiency. Recent studies have implicated HNRNPM in neurodegenerative diseases, particularly ALS and frontotemporal dementia, where RNA metabolism dysregulation is a key pathological feature. The protein's ability to regulate splicing of disease-relevant transcripts makes it a molecule of interest for understanding neurodegeneration mechanisms.[@ramos2015]
Protein Name: HNRNPM - Heterogeneous Nuclear Ribonucleoprotein M
UniProt ID: P61326
Gene: [HNRNPM](/genes/hnrnpm)
Molecular Weight: ~77 kDa (730 amino acids)
Protein Class: RNA-binding protein, Splicing factor
Tissue Expression: Ubiquitous, high in brain, muscle
N-terminal region: Regulatory and interaction surfaces
C-terminal acidic domain: May mediate interactions with other hnRNPs
Nuclear localization signals: NLS sequences for nuclear import
The arrangement of RRMs allows for recognition of diverse RNA sequences, and the protein can also interact with other splicing factors through its glycine-rich domain.[@dreyfuss1993]
Function
HNRNPM performs diverse RNA-processing functions:
Alternative splicing: Regulates inclusion/exclusion of specific exons
Pre-mRNA binding: Associates with nascent pre-mRNA transcripts
mRNA stability: Modulates mRNA half-life through binding
Translation regulation: Affects translational efficiency of target mRNAs
Transcript-specific regulation: Controls splicing of specific disease-relevant transcripts
Nuclear-cytoplasmic transport: Involved in mRNA export
HNRNPM can function as both a splicing activator and repressor depending on the context and binding site location relative to regulated exons.[@han2010]
Role in Neurodegeneration
Amyotrophic Lateral Sclerosis (ALS)
RNA metabolism: Global disruption of RNA processing in ALS
Splicing dysregulation: Alters splicing of ALS-related transcripts
Stress granules: Incorporated into stress granules under stress
[TDP-43](/mechanisms/tdp-43-proteinopathy) pathology: Interacts with TDP-43 in RNA granules
Frontotemporal Dementia
FTD pathology: Altered HNRNPM in FTD brain
RNA granule dynamics: Disrupted stress response
Alternative splicing: Aberrant splicing patterns
Other Neurodegenerative Conditions
Alzheimer disease: Possible HNRNPM alterations
Spinal muscular atrophy: Connection to splicing machinery
Therapeutic Potential
Splicing modifiers: Compounds that restore proper splicing patterns