Hartig et al. 2024 — Stereocilia elongation proteins are long-lived in adult hair cells
Citation: Elli I Hartig, Matthew Day, Amandine Jarysta, Basile Tarchini. “Proteins required for stereocilia elongation during mammalian hair cell development ensure precise and steady heights during adult life.” PNAS 121:e2405455121, 2024. PMID 39320919. DOI 10.1073/pnas.2405455121.
Attribution note: This paper is occasionally misattributed as “Mauriac & Barr-Gillespie 2024” in early STRC audit notes. The correct attribution is Hartig et al. 2024; first author Elli I Hartig, senior author Basile Tarchini.
Numbers that matter
| Parameter | Value | Cell type / method | PMC full text |
|---|---|---|---|
| GPSM2 t½ (HaloTag pulse-chase) | 9.05 days (k = 0.077/d) | Mouse IHC, adult | PMC11459194 |
| GPSM2 t½ (immunolabeling decay) | 10.14 days (k = 0.068/d) | Mouse IHC, adult | PMC11459194 |
| Stereocilia height loss after GPSM2 deletion | 568–695 nm over 12 weeks | Adult IHC, base to apex | PMC11459194 |
| MYO15A enrichment after GPSM2 loss | reduced to 60% of control | Adult IHC | PMC11459194 |
| EPS8 enrichment after GPSM2 loss | reduced to 48% of control | Adult IHC | PMC11459194 |
| WHRN enrichment after GPSM2 loss | reduced to 33% of control | Adult IHC | PMC11459194 |
Full text verified via PMC11459194 (2026-04-25).
Core finding
GPSM2 and its elongation complex partners (MYO15A, WHRN, EPS8) are required not only during development but throughout adult life to maintain stereocilia heights. GPSM2 t½ measured by two independent methods = 9.05 d (HaloTag pulse-chase) and 10.14 d (immunolabeling decay). Loss of GPSM2 in adult IHC causes progressive shortening of ~600 nm over 12 weeks, corresponding to the ~0.5 µm distal tip region where actin turnover occurs.
Relevance for STRC_HL_D modeling
GPSM2 t½ = 9–10 d is the best available published t½ for any specific stereocilia tip-complex protein. Used as an anchor for the STRC_HL_D = 14 d estimate in mrna_lnp_pkpd_integration*.py. The scripts correctly flag this as an OOM estimate; 14 d is within the 9–10 d GPSM2 anchor ± OOM uncertainty.
NOT an STRC-specific measurement. GPSM2 is a motor-scaffold protein; STRC is an extracellular link protein. Different protein class, possibly different turnover mechanism.
Connections
[source]STRC h06 Parameter Provenance Audit 2026-04-23[source]STRC h06 Parameter Provenance Audit 2026-04-25[see-also]2012-zhang-stereocilia-protein-turnover[applies]STRC mRNA Therapy Hypothesis