Table 1.

Dimensional Model Parameters

Symbol	Description	Estimated Values	Legend/Referencesa
${\mathrm{n}}_{\mathrm{m}}$+	number of myosin motors in the cellular protrusion	$550$	A
${\mathrm{F}}_{\mathrm{m}}$+	single myosin motor stall force	$0.6-2.3\mathrm{p}\mathrm{N}$	Chan and Odde (2); Molloy et al. (40); Ishijima et al. (41); Kishino and Yanagida (42); Tyska et al. (43)
${\mathrm{v}}_{\mathrm{u}}$+	myosin unloaded velocity	$120-240$$\mathrm{n}\mathrm{m}·{\mathrm{s}}^{-1}$	Chan and Odde (2); Bangasser et al. (10); Bangasser and Odde (17); Stark et al. (44)
${\mathrm{n}}_{\mathrm{c}}$∗	number of clutches in the cellular protrusion	$470$	B
${\mathrm{k}}_{\mathrm{on}}$∗	clutch association rate constant	$0.1-6$${\mathrm{s}}^{-1}$	Chan and Odde (2); Bangasser et al. (10); Bangasser and Odde (17); Litvinov et al. (45)
${\mathrm{k}}_{\mathrm{off}}$∗	unloaded clutch dissociation kinetic rate constant	$0.1-6.5$${\mathrm{s}}^{-1}$	Chan and Odde (2); Bangasser et al. (10); Bangasser and Odde (17); Litvinov et al. (45); Le et al. (46)
${\mathrm{F}}_{\mathrm{b}}$∗	characteristic clutch-bond rupture force	$1.7\mathrm{p}\mathrm{N}$	C
${\kappa }_{\mathbf{c}}$∗	molecular clutch stiffness	$\left[0.1-2\right]\mathrm{p}\mathrm{N}·{\mathrm{n}\mathrm{m}}^{-1}$	D
$\theta$∗	load-dependent clutch reinforcement strength	adjusted	–
${\mathrm{F}}_{\mathrm{th}}$∗	load-dependent clutch reinforcement threshold force	$5-10$$\mathrm{p}\mathrm{N}$	Yao et al. (47); Yan et al. (48); Yu et al. (49); Yao et al. (50); Mekhdjian et al. (51)
${\mathrm{k}}_{\mathrm{off}}^{\mathrm{catch}}$∗	unloaded clutch catch bond dissociation kinetic rate constant	adjusted	–
${\mathrm{F}}_{\mathrm{b}}^{\mathrm{catch}}$∗	characteristic clutch catch bond rupture force	adjusted	–
${\kappa }_{\mathbf{s}}$#	compliant substrate stiffness	$\left[3.5-3.5\times {10}^4\right]\mathrm{p}\mathrm{N}·{\mu \mathrm{m}}^{-1}$	E

^aParameter values are estimated in the supporting material. Motor parameters (plus symbol), clutch parameters (asterisk), cell environment parameters (hash symbol).