Table 2

Trafficking parametersa

DescriptionValue
EGFR model parameter
SREGFR synthesis rateNRb
kfEGF association rate constant (m min)9.7× 10
krEGF dissociation rate constant (min)0.24
kerUnoccupied EGFR internalization rate constant (min)0.07 ± 0.02
kecEGF internalization rate constant (min)0.10 − 0.25
kec,+ 2C4EGF internalization rate,+ 2C4 (min)0.28 ± 0.02
fxrUnoccupied EGFR recycling fraction0.8c
fxcEGF recycling fraction0.5–0.7
fxc,+ 2C4EGF recycling fraction,+ 2C40.47 ± 0.06
kxcEGF endosomal exit rate constant (min)0.036 ± 0.003
kxc,+ 2C4EGF endosomal exit rate constant,+ 2C4 (min)0.034 ± 0.002
HER2 model parameter
SHHER2 synthesisNR
kehHER2 internalization rate constant, no EGF (min)0.012 ± 0.004
kehHER2 internalization rate constant,+ EGF (min)0.027 − 0.059
fxhHER2 recycling fraction, no EGF0.94 ± 0.03
fxh+HER2 recycling fraction,+ EGF0.94 ± 0.05
kxhHER2 endosomal exit rate constant (min)0.07 ± 0.01
  • a Values are reported as mean ± SD or as a range of values, as appropriate.

  • b NR, not required.

  • c Literature estimate from Ref. 39 .