PIEZO2 Protein
<div class="infobox infobox-protein">
<table>
<tr><th>Protein</th><td>Piezo-type mechanosensitive ion channel component 2 (PIEZO2, FAM38B)</td></tr>
<tr><th>Encoded by</th><td><a href="/genes/piezo2">PIEZO2</a></td></tr>
<tr><th>UniProt</th><td><a href="https://www.uniprot.org/uniprot/Q9H5I5">Q9H5I5</a></td></tr>
<tr><th>Molecular weight</th><td>~318 kDa</td></tr>
<tr><th>Subcellular localization</th><td>Plasma membrane</td></tr>
<tr><th>Protein family</th><td>Piezo mechanosensitive channel family</td></tr>
<tr><th>Key disease links</th><td>Hereditary sensory neuropathy, <a href="/diseases/parkinsons-disease">Parkinson's disease</a>, proprioceptive neurodegeneration</td></tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/aging" style="color:#ef9a9a">Aging</a>, <a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/cancer" style="color:#ef9a9a">Cancer</a>, <a href="/wiki/cardiac" style="color:#ef9a9a">Cardiac</a>, <a href="/wiki/fibrosis" style="color:#ef9a9a">Fibrosis</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">163 edges</a></td>
</tr>
</table>
</div>
Overview
...PIEZO2 Protein
<div class="infobox infobox-protein">
<table>
<tr><th>Protein</th><td>Piezo-type mechanosensitive ion channel component 2 (PIEZO2, FAM38B)</td></tr>
<tr><th>Encoded by</th><td><a href="/genes/piezo2">PIEZO2</a></td></tr>
<tr><th>UniProt</th><td><a href="https://www.uniprot.org/uniprot/Q9H5I5">Q9H5I5</a></td></tr>
<tr><th>Molecular weight</th><td>~318 kDa</td></tr>
<tr><th>Subcellular localization</th><td>Plasma membrane</td></tr>
<tr><th>Protein family</th><td>Piezo mechanosensitive channel family</td></tr>
<tr><th>Key disease links</th><td>Hereditary sensory neuropathy, <a href="/diseases/parkinsons-disease">Parkinson's disease</a>, proprioceptive neurodegeneration</td></tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/aging" style="color:#ef9a9a">Aging</a>, <a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/cancer" style="color:#ef9a9a">Cancer</a>, <a href="/wiki/cardiac" style="color:#ef9a9a">Cardiac</a>, <a href="/wiki/fibrosis" style="color:#ef9a9a">Fibrosis</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">163 edges</a></td>
</tr>
</table>
</div>
Overview
PIEZO2 is the principal mechanosensitive ion channel responsible for light touch sensation, proprioception, and visceral mechanosensation in vertebrates.[@coste2010][@woo2015] Ardem Patapoutian's discovery of PIEZO1 and PIEZO2 was recognized with the 2021 Nobel Prize in Physiology or Medicine. PIEZO2 transduces mechanical force into electrical signals in dorsal root ganglion (DRG) [neurons](/entities/neurons), Merkel cells, and proprioceptive afferents.[@woo2014] Gain-of-function and loss-of-function mutations cause distinct neurological syndromes, while emerging evidence links mechanosensory signaling dysfunction to neurodegenerative processes affecting sensory and proprioceptive circuits.[@chesler2016][@delle2016]
Structure
PIEZO2 is among the largest known ion channels, with each subunit containing 36-38 predicted transmembrane domains arranged in a distinctive propeller-like trimeric architecture.[@zhao2018][@wang2019]
- Blade domains: Three curved blade arms extend outward, forming a dome-shaped structure that senses membrane tension. Each blade contains ~9 repeat modules of 4 transmembrane helices.[@zhao2018]
- Central pore: The C-terminal transmembrane helices from all three subunits converge to form a cation-selective pore (permeant to Ca²⁺, Na⁺, K⁺).[@wang2019]
- Cap domain: An extracellular cap structure above the pore modulates channel gating and is the target of STOML3-mediated sensitization.[@poole2014]
- Beam domain: An intracellular lever arm that connects the blade domains to the pore, transmitting mechanical force from membrane deformation to gate opening.[@zhao2018]
The trimeric architecture creates a large (~25 nm diameter) membrane footprint, allowing PIEZO2 to sense local membrane curvature changes as small as 1-2 nm — explaining its extraordinary sensitivity to light touch.[@wang2019]
Normal Function
PIEZO2 mediates several distinct mechanosensory modalities in the nervous system:
- Light touch: In Merkel cell-neurite complexes and low-threshold mechanoreceptors (LTMRs) of the skin, PIEZO2 converts gentle indentation into rapidly adapting ionic currents that underlie tactile discrimination.[@coste2010][@woo2014]
- Proprioception: In muscle spindle afferents and Golgi tendon organ neurons, PIEZO2 generates the sensory signals required for body position awareness, coordinated movement, and postural control.[@woo2015][@florezpaz2016]
- Visceral mechanosensation: PIEZO2 in vagal and spinal visceral afferents detects lung inflation (Hering-Breuer reflex), bladder distension, and gastrointestinal motility.[@nonomura2017]
- Airway defense: PIEZO2 in airway sensory neurons mediates sneeze and cough reflexes in response to mechanical irritation.[@prescott2020]
Role in Neurodegeneration
Sensory Neuropathy
Loss-of-function mutations in PIEZO2 cause a distinct hereditary sensory neuropathy characterized by profound loss of proprioception and discriminative touch, with preserved pain and temperature sensation.[@chesler2016][@delle2016] Patients exhibit severe sensory ataxia, scoliosis, joint contractures, and progressive proprioceptive failure that worsens with age — suggesting ongoing degeneration of proprioceptive neurons deprived of activity-dependent trophic support.[@chesler2016]
Parkinson's Disease
Proprioceptive deficits are increasingly recognized as early features of [Parkinson's disease](/diseases/parkinsons-disease), preceding classic motor symptoms by years.[@konczak2009] PIEZO2-expressing proprioceptive afferents in the muscle spindle show [alpha-synuclein](/proteins/alpha-synuclein) accumulation in PD patients, and experimental alpha-synuclein injection into DRG neurons disrupts PIEZO2 trafficking to the plasma membrane.[@braak2003] This mechanotransduction failure may contribute to the postural instability and gait difficulties that are among the most disabling and treatment-resistant features of PD.
PIEZO2 expression and function decline with age in DRG neurons, correlating with progressive loss of tactile acuity and proprioceptive precision in the elderly.[@garciamesa2017] This age-dependent PIEZO2 decline may compound neurodegenerative sensory loss and contribute to falls risk in patients with concurrent neurodegeneration.
CBS/PSP Relevance
Corticobasal syndrome ([CBS](/diseases/corticobasal-syndrome)) features profound proprioceptive deficits (limb-kinetic apraxia, alien limb phenomenon) that may partly reflect degeneration of cortical neurons receiving proprioceptive input from PIEZO2-expressing afferents.[@armstrong2013] Whether PIEZO2 peripheral dysfunction contributes to CBS proprioceptive phenotypes remains unexplored but represents a testable hypothesis.
Therapeutic Targeting
- PIEZO2 sensitizers: STOML3 (stomatin-like protein 3) enhances PIEZO2 mechanosensitivity; compounds that mimic this interaction could amplify residual PIEZO2 function in degenerating sensory neurons.[@poole2014]
- Gene therapy: AAV-mediated PIEZO2 delivery to DRG neurons is under preclinical investigation for hereditary sensory neuropathy, with potential applicability to age-related proprioceptive decline.[@chesler2016]
- Mechanotransduction-independent proprioceptive support: Vibrotactile biofeedback devices that bypass PIEZO2-dependent proprioception may provide compensatory spatial awareness for patients with proprioceptive neurodegeneration.[@florezpaz2016]
- Lipid raft modulators: PIEZO2 gating is modulated by local membrane lipid composition; dietary or pharmacological manipulation of membrane cholesterol/phospholipid ratios may tune channel sensitivity.[@borbiro2015]
See Also
- [PIEZO2](/genes/piezo2)
- [PIEZO1 Protein](/proteins/piezo1-protein)
- [Sensory Neuropathy](/diseases/hereditary-sensory-neuropathy)
- [Parkinson's Disease](/diseases/parkinsons-disease)
- [Proprioception](/mechanisms/proprioception)
External Links
- [UniProt: piezo2](https://www.uniprot.org/)
- [PubMed: piezo2](https://pubmed.ncbi.nlm.nih.gov/?term=piezo2+neurodegeneration)
References
[Coste B, Mathur J, Schmidt M, et al, Piezo1 and Piezo2 are essential components of distinct mechanically activated cation channels (2010)](https://doi.org/10.1126/science.1193270)
[Woo SH, Lukacs V, de Nooij JC, et al, Piezo2 is the principal mechanotransduction channel for proprioception (2015)](https://doi.org/10.1038/nn.4162)
[Woo SH, Ranade S, Weyer AD, et al, Piezo2 is required for Merkel-cell mechanotransduction (2014)](https://doi.org/10.1038/nature13251)
[Chesler AT, Szczot M, Bharucha-Goebel D, et al, The role of PIEZO2 in human mechanosensation (2016)](https://doi.org/10.1056/NEJMoa1602812)
[Delle Vedove A, Storbeck M, Heller R, et al, Biallelic loss of proprioception-related PIEZO2 causes muscular atrophy with perinatal respiratory distress, arthrogryposis, and scoliosis (2016)](https://doi.org/10.1016/j.ajhg.2016.07.003)
[Zhao Q, Zhou H, Chi S, et al, Structure and mechanogating mechanism of the Piezo1 channel (2018)](https://doi.org/10.1038/nature25743)
[Wang L, Zhou H, Zhang M, et al, Structure and mechanogating of the mammalian tactile channel PIEZO2 (2019)](https://doi.org/10.1038/s41586-019-1505-8)
[Poole K, Herber R, Heidrich L, et al, Tuning Piezo ion channels to detect molecular-scale movements relevant for fine touch (2014)](https://doi.org/10.1038/ncomms4520)
[Florez-Paz D, Bali KK, Kuner R, et al, A critical role for Piezo2 channels in the mechanotransduction of mouse proprioceptive neurons (2016)](https://doi.org/10.1038/srep25738)
[Nonomura K, Woo SH, Chang RB, et al, Piezo2 senses airway stretch and mediates lung inflation-induced apnoea (2017)](https://doi.org/10.1038/nature22986)
[Prescott SL, Umans BD, Williams EK, et al, An airway protection program revealed by sweeping genetic control of vagal afferents (2020)](https://doi.org/10.1016/j.cell.2020.03.004)
[Konczak J, Corcos DM, Horak F, et al, Proprioception and motor control in Parkinson's disease (2009)](https://doi.org/10.3233/JPD-2009-0185)
[Braak H, Del Tredici K, Rüb U, et al, Staging of brain pathology related to sporadic Parkinson's disease (2003)](https://doi.org/10.1016/S0197-4580(02)
[Garcia-Mesa Y, Garcia-Piqueras J, Garcia B, et al, Merkel cells and Meissner's corpuscles in human digital skin display Piezo2 immunoreactivity (2017)](https://doi.org/10.1002/cne.24560)
[Armstrong MJ, Litvan I, Lang AE, et al, Criteria for the diagnosis of corticobasal degeneration (2013)](https://doi.org/10.1212/WNL.0b013e31827f0fd1)
[Borbiro I, Badheka D, Bhatt DL, et al, Activation of TRPV1 channels inhibits mechanosensitive Piezo channel activity by depleting membrane phosphoinositides (2015)](https://doi.org/10.1126/scisignal.aaa8661)