PT  - JOURNAL ARTICLE
AU  - Brenner, Sibylle
AU  - Berger, Florian
AU  - Rao, Lu
AU  - Nicholas, Matthew P.
AU  - Gennerich, Arne
TI  - Force production of human cytoplasmic dynein is limited by its processivity
AID  - 10.1126/sciadv.aaz4295
DP  - 2020 Apr 01
TA  - Science Advances
PG  - eaaz4295
VI  - 6
IP  - 15
4099  - http://advances.sciencemag.org/content/6/15/eaaz4295.short
4100  - http://advances.sciencemag.org/content/6/15/eaaz4295.full
SO  - Sci Adv2020 Apr 01; 6
AB  - Cytoplasmic dynein is a highly complex motor protein that generates forces toward the minus end of microtubules. Using optical tweezers, we demonstrate that the low processivity (ability to take multiple steps before dissociating) of human dynein limits its force generation due to premature microtubule dissociation. Using a high trap stiffness whereby the motor achieves greater force per step, we reveal that the motor’s true maximal force (“stall force”) is ~2 pN. Furthermore, an average force versus trap stiffness plot yields a hyperbolic curve that plateaus at the stall force. We derive an analytical equation that accurately describes this curve, predicting both stall force and zero-load processivity. This theoretical model describes the behavior of a kinesin motor under low-processivity conditions. Our work clarifies the true stall force and processivity of human dynein and provides a new paradigm for understanding and analyzing molecular motor force generation for weakly processive motors.