SERCA Protein

SERCA Protein

<div class="infobox infobox-protein">
<table>
<tr><th colspan="2">SERCA (Sarco/Endoplasmic Reticulum Ca²⁺-ATPase)</th></tr>
<tr><td>Genes</td><td>[ATP2A1](/genes/atp2a1), [ATP2A2](/genes/atp2a2), [ATP2A3](/genes/atp2a3)</td></tr>
<tr><td>UniProt ID</td><td>[O14983](https://www.uniprot.org/uniprot/O14983) (SERCA1)</td></tr>
<tr><td>PDB</td><td>1DQA, 2ZBD, 3N5K, 6KYT</td></tr>
<tr><td>Molecular Weight</td><td>110 kDa</td></tr>
<tr><td>Localization</td><td>ER/SR membrane</td></tr>
<tr><td>Family</td><td>P-type ATPase family, IIA subgroup</td></tr>
<tr><td>Disease</td><td>Darier Disease, Brody Disease, AD</td></tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>
</div>

Overview

The Sarco/Endoplasmic Reticulum Ca²⁺-ATPase (SERCA) is a P-type ATPase that actively pumps calcium ions from the cytosol into the endoplasmic/sarcoplasmic reticulum. This calcium reuptake is essential for terminating calcium signals, maintaining ER calcium stores, and enabling repeated signaling events. SERCA dysfunction contributes to calcium dyshomeostasis in neurodegeneration.

Structure

SERCA has a characteristic P-type ATPase structure with four functional domains:

A-domain (Actuator): Involved in dephosphorylation and calcium release

P-domain (Phosphorylation): Contains the conserved DKTGT phosphorylation motif

N-domain (Nucleotide-binding): Binds ATP

Transmembrane domain: 10 helices forming the calcium transport pathway

...

SERCA Protein

<div class="infobox infobox-protein">
<table>
<tr><th colspan="2">SERCA (Sarco/Endoplasmic Reticulum Ca²⁺-ATPase)</th></tr>
<tr><td>Genes</td><td>[ATP2A1](/genes/atp2a1), [ATP2A2](/genes/atp2a2), [ATP2A3](/genes/atp2a3)</td></tr>
<tr><td>UniProt ID</td><td>[O14983](https://www.uniprot.org/uniprot/O14983) (SERCA1)</td></tr>
<tr><td>PDB</td><td>1DQA, 2ZBD, 3N5K, 6KYT</td></tr>
<tr><td>Molecular Weight</td><td>110 kDa</td></tr>
<tr><td>Localization</td><td>ER/SR membrane</td></tr>
<tr><td>Family</td><td>P-type ATPase family, IIA subgroup</td></tr>
<tr><td>Disease</td><td>Darier Disease, Brody Disease, AD</td></tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>
</div>

Overview

The Sarco/Endoplasmic Reticulum Ca²⁺-ATPase (SERCA) is a P-type ATPase that actively pumps calcium ions from the cytosol into the endoplasmic/sarcoplasmic reticulum. This calcium reuptake is essential for terminating calcium signals, maintaining ER calcium stores, and enabling repeated signaling events. SERCA dysfunction contributes to calcium dyshomeostasis in neurodegeneration.

Structure

SERCA has a characteristic P-type ATPase structure with four functional domains:

A-domain (Actuator): Involved in dephosphorylation and calcium release

P-domain (Phosphorylation): Contains the conserved DKTGT phosphorylation motif

N-domain (Nucleotide-binding): Binds ATP

Transmembrane domain: 10 helices forming the calcium transport pathway

SERCA cycles through several conformational states (E1-E2 transition):

• E1: High Ca²⁺ affinity, cytosolic-facing binding sites
• E1~P: Phosphorylated, Ca²⁺ occluded
• E2~P: Low Ca²⁺ affinity, luminal release
• E2: Dephosphorylated, reset[@toyoshima2000]

Three isoforms exist:

• SERCA1 (ATP2A1): Fast-twitch skeletal muscle, Brody disease
• SERCA2 (ATP2A2): Widespread, brain (SERCA2b dominant), Darier disease
• SERCA3 (ATP2A3): Limited distribution, secretory cells

Normal Function

SERCA is critical for calcium homeostasis:

Calcium Reuptake: Pumps 2 Ca²⁺ per ATP into ER lumen

ER Calcium Loading: Maintains high luminal Ca²⁺ (mM range)

Signal Termination: Ends Ca²⁺ transients rapidly

Muscle Relaxation: In skeletal/cardiac muscle (SERCA1/2a)

Protein Folding: ER chaperones require Ca²⁺ for function

Store-Operated Calcium Entry (SOCE): STIM senses ER depletion via SERCA

SERCA activity is regulated by:

• Phospholamban: Inhibitory, relieved by PKA phosphorylation
• Sarcolipin: Inhibitory, controls heat production
• Calmodulin: Modulates activity
• ER calcium levels: Product inhibition at high luminal Ca²⁺

Role in Neurodegeneration

Alzheimer's Disease

SERCA dysfunction in AD has complex implications[@green2006]:

Downregulation observed:

• Reduced SERCA2b expression in AD brain
• Contributes to ER calcium depletion
• Impaired protein folding capacity

[Aβ](/proteins/amyloid-beta) effects on SERCA:

• Aβ oligomers may inhibit SERCA activity
• ER stress from reduced Ca²⁺ stores
• Compromised [UPR](/entities/unfolded-protein-response) response

Therapeutic considerations:

• SERCA activation may improve ER function
• BUT: Increased ER Ca²⁺ may enhance IP₃R/RyR release → excitotoxicity
• Balanced approach needed

Parkinson's Disease

SERCA involvement in PD:

• [α-synuclein](/proteins/alpha-synuclein): Inhibits SERCA in cellular models
• MPTP models: Reduced SERCA expression
• DJ-1: Protects SERCA from oxidative damage[@zang2013]

Huntington's Disease

• mHtt disrupts ER calcium handling
• SERCA function compromised
• Contributes to calcium dyshomeostasis

Bipolar Disorder and Depression

• SERCA implicated in mood regulation
• Some mood stabilizers affect SERCA
• Calcium signaling dysregulation hypothesis

Therapeutic Targeting

| Agent | Mechanism | Status |
|-------|-----------|--------|
| CDN1163 | SERCA activator | Preclinical |
| Istaroxime | SERCA2a activator | Phase II (heart failure) |
| Thapsigargin | SERCA inhibitor (research tool) | Not therapeutic |
| Ispinesib | SERCA2b upregulation | Preclinical |
| Gene therapy | AAV-SERCA2a | Clinical (cardiac) |

SERCA activation strategy:

• May improve ER function in neurodegeneration
• Concern: Enhanced Ca²⁺ release via IP₃R/RyR
• Isoform-specific targeting needed

See Also

• IP₃ Receptor - ER Ca²⁺ release channel
• [Ryanodine Receptor - ER Ca²⁺ release channel](/entities/ryanodine-receptor)
• STIM1 - ER Ca²⁺ sensor
• Calcium Dyshomeostasis
• [ER Stress](/mechanisms/er-stress-pathway)