Hair Cell Biophysical Reference Table

Cell-biophysical baselines for E15 chick utricle hair cells (FM1-43 high) and supporting cells / progenitors (FM1-43 low), measured directly by Zhu 2019 eLife using FACS-volumetry and nanoPOTS single-cell mass spectrometry.

Verbatim values

#ParameterValue (mean ± SD or SEM)MethodSource page
1FM1-43 high cell volume (hair cell)1.01 ± 0.20 pL (N=9)post-FACS volumetricZhu 2019 p.3
2FM1-43 low cell volume (supporting cell)0.67 ± 0.15 pL (N=8)post-FACS volumetricZhu 2019 p.3
3HeLa volume (comparator)4.9 ± 1.1 pL (N=5)same methodZhu 2019 p.3
4Stereocilia per E15 utricle hair cell72 ± 8 (N=26)wholemount counts, striolar + extrastriolarZhu 2019 p.5
5Total actin molecules per E15 hair cell~15,000,000ACTG1 riBAQ × cell volume × AvogadroZhu 2019 p.5
6Actin molecules per E15 stereocilium~200,000derived from rows 4 + 5Zhu 2019 p.5
7Actin per E20 stereocilium (later development)~400,000Shin 2013 priorZhu 2019 p.5, citing Shin 2013
8Unique peptides identified, single FM1-43-high cell~200 (50% MS/MS, 50% Match)nanoPOTS LC-MS/MSZhu 2019 p.4 (Fig 1D)
9Unique peptides identified, 20-cell FM1-43-high pool~2,500 (~70% MS/MS)sameZhu 2019 p.4 (Fig 1D)
10Unique peptides identified, 20-cell FM1-43-low pool~1,200 (~60% MS/MS)sameZhu 2019 p.4 (Fig 1E)
11Proteins / protein groups, single FM1-43-high cell~60identification thresholdZhu 2019 p.4 (Fig 1G)
12Proteins / protein groups, 20-cell FM1-43-high pool~600sameZhu 2019 p.4 (Fig 1G)
13Total proteins detectable in chick utricle epithelium (1D LC)~3,000bulk 1D-LCShin 2013 (cited Zhu 2019 p.7)

Cross-cell sanity checks

  • HeLa is the volume of a hair cell and the volume of a supporting cell. Detection count scales sub-linearly because of nanowell adsorption (Zhu 2019 Fig 1F).
  • Actin riBAQ (0.043) × ~15M total protein ≈ ~600,000 ACTG1 monomers per single hair cell — consistent with the 15M figure cited at p.5 once the population-level normalization is applied (paper estimates per cell, not per cell × replicates).

Derived quantities (calculation, NOT in paper)

Derived quantityValueDerivation
Mature OHC stereocilium volume (200 nm Ø, 3 μm long)~9.4 × 10⁻¹⁷ Lπ·r²·h
Local [actin] in one stereocilium (200,000 mol / volume)~3.5 mM totalAvogadro on row 6
[F-actin] assuming 90% filamentous~3.15 mMderived
Working bracket1–5 mM [F-actin] in mature stereocilium corebracketed for h09 modeling

Use in modeling

  • h09 hydrogel competition models: Use [F-actin] = 1–5 mM for stereocilium core, [G-actin] ≈ 86% of total cellular actin (after TMSB4X subtraction; see TMSB4X Actin Buffering Stoichiometry Hair vs Supporting Cells).
  • Cell-volume estimates for converting molar amounts to molecule counts in any single-cell-resolved hair-cell calculation.

Connections