HNRNPL (Heterogeneous Nuclear Ribonucleoprotein L) encodes an RNA-binding protein that plays critical roles in post-transcriptional gene regulation[1]. As a member of the hnRNP family, HNRNPL is involved in alternative splicing, mRNA stability, translation regulation, and various aspects of RNA processing. The protein contains multiple RNA recognition motifs (RRMs) that enable it to bind to specific RNA sequences and participate in the formation of ribonucleoprotein complexes essential for proper cellular function.
HNRNPL has been increasingly recognized for its important roles in neuronal function and neurodegeneration[2]. Dysregulation of HNRNPL and its associated splicing targets has been implicated in Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and other neurological disorders. This page provides a comprehensive overview of HNRNPL's molecular function, structural features, disease associations, and therapeutic implications.
| Property | Value |
|---|---|
| Gene Symbol | HNRNPL |
| Full Name | Heterogeneous Nuclear Ribonucleoprotein L |
| Alternative Names | hnRNP L, Plectin |
| Chromosomal Location | 19q13.31 |
| NCBI Gene ID | 3191 |
| OMIM ID | 607073 |
| Ensembl ID | ENSG00000130816 |
| UniProt ID | P14866 |
| Protein Length | 589 amino acids |
| Molecular Weight | ~64 kDa |
| Associated Diseases | ALS, AD, PD, Autoimmune disease, Cancer |
HNRNPL contains several functional domains[3]:
RNA Recognition Motifs (RRMs): Three RRMs (RRM1, RRM2, RRM3) located in the central region
** glycine-rich Region**: Contains multiple glycine repeats
Proline-rich Region: Involved in protein-protein interactions
N-terminal Region: Regulatory functions
The RRMs of HNRNPL recognize specific RNA sequences:
HNRNPL is a key regulator of alternative splicing[1:1]:
Key Splicing Functions:
Beyond splicing, HNRNPL regulates[4]:
HNRNPL interacts with the telomerase complex:
HNRNPL is recruited to stress granules under cellular stress[5]:
HNRNPL shows ubiquitous expression across tissues:
| Tissue | Expression Level |
|---|---|
| Brain (cortex, hippocampus) | High |
| Heart | High |
| Liver | High |
| Lung | Moderate |
| Kidney | Moderate |
| Skeletal muscle | Moderate |
| Testis | High |
| Most tissues | Moderate-high |
Within the nervous system, HNRNPL is expressed in[2:1]:
HNRNPL is significantly implicated in ALS pathogenesis[6][7]:
Key Evidence:
HNRNPL contributes to AD through multiple mechanisms[8]:
Key Evidence:
HNRNPL plays important roles in PD pathogenesis[9]:
HNRNPL dysfunction leads to neurodegeneration through:
HNRNPL regulates splicing of several neurodegeneration-relevant genes:
| Gene | Function | HNRNPL Effect |
|---|---|---|
| MAPT | Tau isoforms | Alternative splicing |
| SNCA | α-synuclein | Transcript variants |
| SOD1 | Antioxidant | Splicing regulation |
| TDP-43 | RNA processing | Interaction |
| VAPB | ER function | Splicing |
HNRNPL interacts with several key proteins:
| Partner | Interaction | Context |
|---|---|---|
| HNRNPA1 | Direct binding | Splicing regulation |
| HNRNPA2B1 | Complex formation | RNA processing |
| TDP-43 | Functional interaction | ALS pathology |
| SRSF1 | Co-regulation | Splicing |
| PABPN1 | Binding | mRNA processing |
Targeting HNRNPL represents a promising approach[10]:
HNRNPL's RRMs (RNA Recognition Motifs) enable precise RNA binding[3:1]:
RRM1 (aa 150-220):
RRM2 (aa 240-310):
RRM3 (aa 340-420):
HNRNPL functions in multiple splicing complexes:
| Complex | Function | HNRNPL Role |
|---|---|---|
| NTC | Core spliceosome | Activator |
| HshnRNP | hnRNP particles | Assembly |
| SR complex | Splicing regulation | Co-activator |
| EXM | Exon definition | Enhancer binding |
HNRNPL activity is regulated by:
HNRNPL dysfunction contributes to ALS through multiple pathways[6:1][7:1]:
Splicing Dysregulation:
Stress Granule Pathology:
TDP-43 Interaction:
HNRNPL contributes to AD through[8:1]:
Tau Splicing Dysregulation:
APP Processing:
Synaptic Dysfunction:
HNRNPL in PD involves[9:1]:
α-Synuclein Regulation:
Mitochondrial Function:
Dopaminergic Vulnerability:
| Tool | Application | Status |
|---|---|---|
| siRNA | Knockdown | Validated |
| CRISPR | Gene editing | In development |
| ASOs | Splice modulation | Preclinical |
| Small molecules | Target modulation | Discovery |
HNRNPL as a biomarker:
Splice-Switching Oligonucleotides (SSOs):
Small Molecule Modulators:
Currently no direct HNRNPL-targeted trials, but related approaches:
| Protein | Primary Function | Disease Links |
|---|---|---|
| HNRNPL | Splicing regulation | ALS, AD, PD |
| HNRNPA1 | Telomere maintenance | ALS, Inclusion body myositis |
| HNRNPA2B1 | RNA processing | ALS, PD |
| HNRNPQ | Translation | ALS |
| HNRNPD | mRNA stability | Cancer, ALS |
HNRNPL (Heterogeneous Nuclear Ribonucleoprotein L) is an RNA-binding protein with critical roles in alternative splicing, mRNA stability, and stress response. Through its three RNA recognition motifs, HNRNPL recognizes CA-rich elements and regulates the splicing of numerous transcripts relevant to neurodegeneration.
Dysregulation of HNRNPL contributes to multiple neurodegenerative diseases including ALS, Alzheimer's disease, and Parkinson's disease. In ALS, HNRNPL mutations and altered splicing patterns contribute to disease pathogenesis. In AD, HNRNPL affects tau splicing and APP processing. In PD, HNRNPL modulates α-synuclein transcript variants and mitochondrial function.
Therapeutic targeting of HNRNPL through splicing modulators, gene therapy, and RNA-targeting approaches represents a promising strategy for neurodegenerative disease treatment. Understanding the precise mechanisms of HNRNPL dysfunction will be essential for developing effective therapies.
| Mechanism | Effect | Therapeutic Target |
|---|---|---|
| TDP-43 interaction | Compensatory splicing regulation | Splicing modulators |
| Stress granule dynamics | Altered stress response | Granule inhibitors |
| Motor neuron splicing | Loss of functional isoforms | ASO therapy |
| Mitochondrial transcripts | Energy metabolism defects | Gene therapy |
Liu X, et al. HNRNPL in alternative splicing. 2015. ↩︎ ↩︎
Rahman MA, et al. HNRNPL and neuronal function. Journal of Neuroscience Research. 2015. ↩︎ ↩︎
House RP, et al. hnRNP L in pre-mRNA processing and splicing. Wiley Interdisciplinary Reviews: RNA. 2010. ↩︎ ↩︎
Hutchinson JN, et al. HNRNPL in cancer and disease. Cancer Research. 2012. ↩︎
Liu W, et al. hnRNP L in RNA granule formation. Journal of Cell Science. 2020. ↩︎
Zong L, et al. HNRNPL mutations and neurodegenerative disease. Human Molecular Genetics. 2019. ↩︎ ↩︎
Kim H, et al. Therapeutic targeting of HNRNPL in ALS. Brain. 2024. ↩︎ ↩︎
Chen Y, et al. HNRNPL in Alzheimer's disease. Neurobiology of Aging. 2017. ↩︎ ↩︎
Wang L, et al. HNRNPL in Parkinson's disease models. Acta Neuropathologica. 2022. ↩︎ ↩︎
Zhou Q, et al. RNA binding proteins in neurodegeneration focus on HNRNPL family. Nature Reviews Neuroscience. 2023. ↩︎