| LIMP2 (SCARB2) | |
|---|---|
| Full Name | Lysosomal Integral Membrane Protein 2 |
| Gene Symbol | LIMP2 (also SCARB2) |
| Chromosomal Location | 4q13 |
| NCBI Gene ID | 8740 |
| OMIM ID | 613648 |
| Ensembl ID | ENSG00000110067 |
| UniProt ID | Q8N3U4 |
| Associated Diseases | Parkinson's Disease, Gaucher Disease, Metabolic Disorders |
LIMP2 (Lysosomal Integral Membrane Protein 2), also known as SCARB2 (Scavenger Receptor Class B Member 2), is a lysosomal transmembrane protein that serves as a critical receptor for glucocerebrosidase (GCase, encoded by the GBA gene). LIMP2 is essential for proper lysosomal enzyme trafficking and function. Mutations in LIMP2 cause a form of Gaucher disease, and genetic variants in both LIMP2 and GBA are strongly associated with increased Parkinson's disease risk, establishing a direct link between lysosomal dysfunction and neurodegeneration[1][2].
The LIMP2-GBA axis represents one of the most significant genetic links between Gaucher disease and Parkinson's disease, providing insight into how lysosomal storage disorders may predispose individuals to subsequent neurodegenerative processes[3].
LIMP2 is a type I transmembrane protein with the following structural features:
LIMP2 performs a critical function as the lysosomal receptor for glucocerebrosidase (GCase):
This transport mechanism is essential for maintaining normal lysosomal GCase activity. Loss of LIMP2 function leads to GCase mislocalization and reduced lysosomal enzymatic activity[4].
The LIMP2-GBA pathway is profoundly implicated in PD pathogenesis through multiple mechanisms:
LIMP2 may play a role in AD through:
LIMP2 represents a promising therapeutic target for Parkinson's disease:
| Approach | Description | Development Status |
|---|---|---|
| GCase augmentation | Increase GCase activity through recombinant enzyme or gene therapy | Clinical trials for Gaucher/PD |
| Small molecule chaperones | Stabilize mutant GCase and enhance trafficking | Preclinical/early clinical |
| LIMP2 modulators | Enhance LIMP2 function or expression | Research |
| Substrate reduction | Reduce glucosylceramide accumulation | Clinical trials |
LIMP2 is widely expressed with highest levels in:
In the brain, LIMP2 is expressed in:
Rothaug M, Zunke F, Mazzulli JR, et al. LIMP-2 expression is required for proper lysosomal function. Acta Neuropathologica Communications. 2014. ↩︎ ↩︎
Blanz J, Saftig P, Schwake M. LIMP-2 deficiency leads to neurological disease. EMBO Molecular Medicine. 2014. ↩︎
Burbulla LF, Krainc D. The role of GBA and LIMP2 in Parkinson disease. Experimental Neurobiology. 2019. ↩︎ ↩︎
Reczek D, Schwake M, Schröder J, et al. LIMP-2 is a receptor for lysosomal targeting of mannose-6-phosphate receptor. Journal of Cell Science. 2007. ↩︎
Mazzulli JR, Zunke F, Tsunemi T, et al. Activation of beta-glucoceresidase reduces alpha-synuclein in models of Parkinson disease. Brain. 2016. ↩︎ ↩︎
Sardi SP, Clarke J, Kinnecom C, et al. CNS expression of glucocerebrosidase corrects alpha-synuclein pathology in a mouse model of Gaucher-related synucleinopathy. Journal of Clinical Investigation. 2011. ↩︎ ↩︎
Yang SY, Chang YP, Lee AY, et al. LIMP2 variants associated with Parkinson's disease risk. Movement Disorders. 2020. ↩︎
Grab GA, Chen H, Geng Y, et al. LIMP-2 in the brain: a lysosomal receptor for amyloid-beta and glucocerebrosidase. Journal of Neural Transmission. 2013. ↩︎