Abstract
We consider a stochastic differential equation in a strip, with coefficients suitably chosen to describe the acto-myosin interaction subject to time-varying forces. By simulating trajectories of the stochastic dynamics via an Euler discretization-based algorithm, we fit experimental data and determine the values of involved parameters. The steps of the myosin are represented by the exit events from the strip. Motivated by these results, we propose a specific stochastic model based on the corresponding time-inhomogeneous Gauss-Markov and diffusion process evolving between two absorbing boundaries. We specify the mean and covariance functions of the stochastic modeling process taking into account time-dependent forces including the effect of an external load. We accurately determine the probability density function (pdf) of the first exit time (FET) from the strip by solving a system of two non singular second-type Volterra integral equations via a numerical quadrature. We provide numerical estimations of the mean of FET as approximations of the dwell-time of the proteins dynamics. The percentage of backward steps is given in agreement to experimental data. Numerical and simulation results are compared and discussed.
Similar content being viewed by others
Notes
Here, we call FET from a strip the originally two-boundary FPT random variable defined by Nobile et al. (2006).
In this paper we use \((\prime )\) to indicate the derivative of the function with respect to its own argument; in particular in (1) \((\prime )\) is for the space derivative and \((\cdot )\) denotes the time derivative.
The adjectives “short” and “long” used for the exit times are referred to the characteristic time \(\theta \).
References
Arnold L (1974) Stochastic differential equations: theory and applications. Wiley-Interscience, New York
Bershitsky SY, Tsaturyan AK, Bershitskaya ON, Mashanov GI, Brown P, Burns R, Ferenczi MA (1997) Muscle force is generated by myosin heads stereospecifically attached to actin. Nature 388:186–190
Bezrukov SM, Schimansky-Geier L, Schmid G (2014) Brownian motion in confined geometries. Eur Phys J Spec Top 223:3021–3025
Buonocore A, Caputo L, Ishii Y, Pirozzi E, Yanagida T, Ricciardi LM (2005) On Myosin II dynamics in the presence of external loads. BioSystems 81:165–177
Buonocore A, Caputo L, Nobile AG, Pirozzi E (2015) Restricted Ornstein-Uhlenbeck process and applications in neuronal models with periodic input signals. J Comput Appl Math 285:59–71
Buonocore A, Caputo L, Pirozzi E (2007a) On a pulsating Brownian motor and its characterization. Math Biosci 207:387–401
Buonocore A, Caputo L, Pirozzi E, Ricciardi LM (2007b) Simulation ofMyosin II dynamics modeled by a pulsating ratchet with double-wellpotentials. In: Moreno-Diaz R, Pichler F, Quesada-Arencibia A,Lecture Notes in Computer Science, 4739, Computer Aided SystemTheory - EUROCAST 2007. Springer-Verlag, Berlin, pp 154–162
Buonocore A, Caputo L, Pirozzi E, Ricciardi LM (2011) The first passage time problem for Gauss-Diffusion processes: Algorithmic approaches and applications to lif neuronal model. Methodol Comput Appl Probab 13:29–57
Buonocore A, Di Crescenzo A, Giorno V, Nobile AG, Ricciardi LM (2009) A Markov chain-based model for actomyosin dynamics. Sci Math Jpn 70(2):159–174
Buonocore A, Di Crescenzo A, Martinucci B, Ricciardi LM (2003) A stochastic model for the stepwise motion in actomyosin dynamics. Sci Math Jpn 58:245–254
Cooke R (1997) Actomyosin interaction in striated muscle. Physiol Rev 77:671–697
Cyranoski D (2000) Swimming against the tide. Nature 408:764–766
Di Nardo E, Nobile AG, Pirozzi E, Ricciardi LM (2001) A computational approach to first-passage- time problems for Gauss-Markov processes. Adv Appl Prob 33:453–482
D’Onofrio G, Pirozzi E (2015) On Two-Boundary First Exit Time of Gauss-Diffusion Processes: closed-form results and biological modeling. Lect Notes Semin Interdiscip Mat 12:111–124
D’Onofrio G, Pirozzi E (2016) Successive spike times predicted by a stochastic neuronal model with a variable input signal. Math Biosci Eng 13(3):495–507
Finer JT, Simmons RM, Spudich JA (1994) Single myosin molecule mechanics: piconewton forces and nanometre steps. Nature 368:113–119
Kitamura K, Tokunaga M, Iwane AH, Yanagida T (1999) A single myosin head moves along an actin filament with regular steps of 5.3 nanometres. Nature 397:129–134
Magnasco MO, Stolovitzky G (1998) Feynman’s Ratchet and Pawl. J Stat Phys 93(3–4):615–632
Masuda T (2008) A possible mechanism for determining the directionality of myosin molecular motors. Biosystems 93(3):172–180
Masuda T (2013) Molecular dynamics simulation of a myosin subfragment-1 dockingwith an actin filament. BioSystems 113:144–148
Molloy JE, Burns JE, Kendrick-Jones J, Tregear RT, White DC (1995) Movement and force produced by a single myosin head. Nature 378:209–212
Nobile AG, Pirozzi E, Ricciardi LM (2006) On the two-boundary first-passage time for a class of Markov processes. Sci Math Jpn 64(2):421–442
Oosawa F, Hayashi S (1986) The loose coupling mechanism in molecular machines of living cells. Adv Biophys 22:151–183
Oosawa F (2000) The loose coupling mechanism in molecular machines of living cells. Genes Cells 5:9–16
Radtke PK, Schimansky-Geier L (2012) Directed transport of confined Brownian particles with torque. Phys Rev E 85(5):051110
Reimann P (2002) Brownian motors: noisy transport far from equilibrium. Phys Rep 361:57–265
Spudich JA (1994) How molecular motors work. Nature 372:515–518
Taillefumier T, Magnasco MO (2008) A Haar-like construction for the ornstein uhlenbeck process. J Stat Phys 132(2):397–415
Taillefumier T, Magnasco MO (2010) A fast algorithm for the first-passage times of Gauss-Markov processes with Holder continuous boundaries. J Stat Phys 140(6):1–27
Takagi Y, Homsher EE, Goldman YE, Shuman H (2006) Force generation in single conventional actomyosin complexes under high dynamic load. Biophys J 90(4):1295–1307
Wang H, Oster G (2002) Ratchets, power strokes, and molecular motors. Appl Phys A 75:315–323
Yanagida T, Arata T, Oosawa F (1985) Sliding distance of actin filament induced by a myosin cross-bridge during one ATP hydrolysis cycle. Nature 316:366–369
Acknowledgments
We thank the Editor and the anonymous reviewers for their constructive comments and suggestions. We also thank Angelo Pirozzi, student of Medicine at the University of Napoli Federico II, for the enlightening discussion on some biological aspects which helped us in the writing of subsection 2.1. This work was partially supported by Gruppo Nazionale per il Calcolo Scientifico (GNCS-INdAM).
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
D’Onofrio, G., Pirozzi, E. Two-boundary first exit time of Gauss-Markov processes for stochastic modeling of acto-myosin dynamics. J. Math. Biol. 74, 1511–1531 (2017). https://doi.org/10.1007/s00285-016-1061-x
Received:
Revised:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00285-016-1061-x