CERS2 (Ceramide Synthase 2), also known as LASS2 (Longevity Assurance Homolog 2) or TISH1, is a critical enzyme in the ceramide biosynthesis pathway that synthesizes very-long-chain ceramides (C20-C22). Originally identified as a longevity assurance gene, CERS2 has evolved to be recognized as a central player in neuronal lipid metabolism with profound implications for Alzheimer's disease (AD), Parkinson's disease (PD), and other neurodegenerative conditions [@golf201].
This 383-amino acid protein localizes to the endoplasmic reticulum (ER) where it catalyzes the N-acylation of sphingosine with very-long-chain fatty acyl-CoAs, producing C20- and C22-ceramides that are essential for neuronal membrane structure, signaling, and survival [@grosch2016]. Unlike other ceramide synthase family members, CERS2 exhibits unique substrate specificity that makes it particularly important in the brain, where very-long-chain ceramides constitute up to 30% of total sphingolipids [@golf212].
CERS2 (Ceramide Synthase 2), also known as LASS2 (Longevity Assurance Homolog 2) or TISH1, is a critical enzyme in the ceramide biosynthesis pathway that synthesizes very-long-chain ceramides (C20-C22). Originally identified as a longevity assurance gene, CERS2 has evolved to be recognized as a central player in neuronal lipid metabolism with profound implications for Alzheimer's disease (AD), Parkinson's disease (PD), and other neurodegenerative conditions [@golf201].
This 383-amino acid protein localizes to the endoplasmic reticulum (ER) where it catalyzes the N-acylation of sphingosine with very-long-chain fatty acyl-CoAs, producing C20- and C22-ceramides that are essential for neuronal membrane structure, signaling, and survival [@grosch2016]. Unlike other ceramide synthase family members, CERS2 exhibits unique substrate specificity that makes it particularly important in the brain, where very-long-chain ceramides constitute up to 30% of total sphingolipids [@golf212].
<div class="infobox infobox-protein">
<table>
<tr><th colspan="2" style="background:#e8f4f8; text-align:center; font-size:1.1em;">CERS2 Protein (Ceramide Synthase 2)</th></tr>
<tr><td><strong>Protein Name</strong></td><td>Ceramide Synthase 2</td></tr>
<tr><td><strong>Gene Symbol</strong></td><td><a href="/genes/cers2">CERS2</a></td></tr>
<tr><td><strong>Alternative Names</strong></td><td>LASS2, TISH1, LAG1 homolog</td></tr>
<tr><td><strong>Chromosome</strong></td><td>12q24.31</td></tr>
<tr><td><strong>NCBI Gene ID</strong></td><td><a href="https://www.ncbi.nlm.nih.gov/gene/29956" target="_blank">29956</a></td></tr>
<tr><td><strong>UniProt ID</strong></td><td><a href="https://www.uniprot.org/uniprot/Q9H0K0" target="_blank">Q9H0K0</a></td></tr>
<tr><td><strong>Molecular Weight</strong></td><td>44 kDa (383 amino acids)</td></tr>
<tr><td><strong>Subcellular Location</strong></td><td>Endoplasmic reticulum</td></tr>
<tr><td><strong>Protein Family</strong></td><td>Ceramide synthase (CerS) family</td></tr>
<tr><td><strong>Tissue Expression</strong></td><td>High in brain, liver, kidney</td></tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/ad" style="color:#ef9a9a">AD</a>, <a href="/wiki/ami" style="color:#ef9a9a">AMI</a>, <a href="/wiki/ards" style="color:#ef9a9a">ARDS</a>, <a href="/wiki/arm" style="color:#ef9a9a">ARM</a>, <a href="/wiki/aging" style="color:#ef9a9a">Aging</a></td>
</tr>
<tr>
<td class="label">SciDEX Hypotheses</td>
<td><a href="/hypothesis/h-6657f7cd" style="color:#ce93d8" title="Score: 0.42">Sphingolipid Metabolism Reprogramming...</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">98 edges</a></td>
</tr>
</table>
</div>
CERS2 possesses the characteristic domain architecture shared by all ceramide synthase family members:
CERS2 catalyzes the condensation of sphinganine or sphingosine with very-long-chain fatty acyl-CoA:
$$\text{Sphingosine} + \text{C20-C22 acyl-CoA} \xrightarrow{\text{CERS2}} \text{C20-C22 ceramide} + \text{CoA}$$
The reaction proceeds through a ping-pong mechanism where the acyl-CoA first binds to the enzyme, followed by sphingosine binding, and then product release.
| CerS | Gene | Primary Substrate | Main Product | Brain Expression |
|------|------|-------------------|--------------|-----------------|
| CERS1 | CERS1 | C18:0 acyl-CoA | C18-ceramide | High (neurons) |
| CERS2 | CERS2 | C20:0, C22:0 acyl-CoA | C20-C22 ceramides | High (broad) |
| CERS3 | CERS3 | C14-C30 acyl-CoA | Ultra-long-chain | Low |
| CERS4 | CERS4 | C18-C20 acyl-CoA | C18-C20 ceramides | Moderate |
| CERS5 | CERS5 | C16:0 acyl-CoA | C16-ceramide | Moderate |
| CERS6 | CERS6 | C14:0 acyl-CoA | C14-ceramide | High (brainstem) |
This substrate specificity has critical implications for neuronal function, as C20- and C22-ceramides are particularly enriched in synaptic membranes, myelin sheaths, and lipid rafts [@golf212].
CERS2 plays a central role in the de novo ceramide synthesis pathway. Following ceramide generation at the ER, these lipids are transported to the Golgi apparatus for further metabolism into complex sphingolipids:
CERS2-derived very-long-chain ceramides have unique biological functions:
CERS2 is particularly important for ferroptosis, an iron-dependent form of non-apoptotic cell death characterized by lipid peroxidation:
CERS2 dysregulation is increasingly recognized as a significant contributor to AD pathogenesis. Multiple mechanisms have been identified:
Amyloid-beta metabolism: CERS2 suppresses Aβ-induced neurotoxicity through autophagy regulation. Meng et al. demonstrated that CERS2 deficiency exacerbates Aβ toxicity, while overexpression protects neurons through enhanced autophagic clearance [@meng2019]. The mechanism involves regulation of Beclin-1, LC3-II, and p62 protein levels.
Tau pathology: CERS2 deficiency accelerates tau hyperphosphorylation and aggregation. Chen et al. showed that CERS2 knockout in APP/PS1 mice significantly increases phosphorylated tau at Ser396, Thr231, and AT8 epitopes [@golf213]. This is mediated through dysregulated GSK-3β activity and impaired PP2A function.
Synaptic dysfunction: CERS2 is essential for synaptic plasticity and memory formation. Zhao et al. demonstrated that CERS2 deficiency leads to impaired long-term potentiation (LTP), reduced synaptic density, and spatial memory deficits [@golf202]. These effects involve NMDA receptor trafficking dysregulation.
Cognitive decline: Zhang et al. showed that CerS2 deficiency accelerates age-related cognitive decline in APP/PS1 mice, with exacerbation of amyloid pathology and synaptic loss [@golf199].
Neuroinflammation: CERS2 deficiency in microglia promotes a pro-inflammatory phenotype with elevated IL-1β, TNF-α, and IL-6 production, creating a feed-forward loop of neuronal damage [@golf210].
CERS2 dysfunction plays multiple roles in PD pathogenesis:
Mitochondrial quality control: CERS2 regulates mitophagy in dopaminergic neurons. Xu et al. demonstrated that CERS2 deficiency leads to impaired Pink1/Parkin-mediated mitochondrial clearance, accumulated mitochondrial damage, and increased oxidative stress [@golf205].
Dopaminergic neuron vulnerability: CERS2 deficiency specifically increases vulnerability of dopaminergic neurons, which are selectively lost in PD. This involves both mitochondrial dysfunction and increased ferroptosis susceptibility.
Neuroinflammation: Wang et al. showed that CERS2 regulates neuroinflammation through NF-κB signaling in PD models [@golf200]. CERS2 overexpression suppresses microglial activation and reduces dopaminergic neuron loss in 6-OHDA models.
Genetic associations: Martinez et al. identified CERS2 promoter polymorphisms associated with increased PD risk, correlating with reduced CERS2 expression [@golf208].
Lipidomic alterations: Chen et al. demonstrated specific alterations in C20-C22 ceramides in PD substantia nigra using mass spectrometry-based lipidomics [@golf204].
Ceramide metabolism dysregulation is a feature of ALS pathology. Brown et al. demonstrated elevated ceramide levels in ALS motor cortex, with altered expression of multiple CerS isoforms including CERS2 [@golf207]. The functional significance involves ER stress and mitochondrial dysfunction pathways leading to motor neuron death.
Kim et al. identified CERS2 mutations in patients with hereditary spastic paraplegia, demonstrating that CERS2 haploinsufficiency causes neurological deficits [@golf203].
CERS2 plays a crucial role in regulating autophagy through multiple mechanisms:
CERS2 maintains mitochondrial homeostasis through:
CERS2 deficiency induces endoplasmic reticulum stress:
CERS2 regulates neuroinflammation through:
CERS2 protects against oxidative stress through:
| Approach | Mechanism | Status | Development Stage |
|----------|-----------|--------|-------------------|
| Small molecule activators | Increase CERS2 expression/activity | Research | Preclinical |
| Gene therapy (AAV-CERS2) | Viral vector overexpression | Preclinical | Animal testing |
| Substrate supplementation | C22:0 fatty acid administration | Research | Cell culture |
| Ferroptosis inhibitors | Downstream protection | Preclinical | Animal testing |
Rationale for therapeutic combinations:
Mass spectrometry-based lipidomics enables precise measurement of ceramide species:
CERS2 (Ceramide Synthase 2) is a critical enzyme in neuronal sphingolipid metabolism with profound implications for neurodegenerative disease. CERS2 synthesizes very-long-chain ceramides (C20-C22) that are essential for membrane structure, lipid raft organization, and cellular signaling. In Alzheimer's disease, CERS2 deficiency contributes to impaired amyloid-beta clearance, exacerbated tau pathology, synaptic dysfunction, and neuroinflammation. In Parkinson's disease, CERS2 dysfunction leads to mitochondrial quality control deficits, increased oxidative stress, enhanced neuroinflammation, and dopaminergic neuron vulnerability. The enzyme also plays a critical role in regulating ferroptosis, an iron-dependent cell death pathway increasingly implicated in neurodegeneration. Therapeutic targeting of CERS2 through small molecule agonists, gene therapy, or downstream pathway modulators represents a promising strategy for neuroprotection. Further research is needed to fully elucidate CERS2 function and develop effective clinical interventions.