Link to the University of Pittsburgh Homepage
Link to the University Library System Homepage Link to the Contact Us Form

Mathematical models of branching actin networks: Results and methods.

Smith, Daniel (2013) Mathematical models of branching actin networks: Results and methods. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

This is the latest version of this item.

Primary Text

Download (2MB) | Preview


Branching actin networks are made up of polymerous actin filaments and play a principle role in cell motility and other cellular processes. Inside the lamellipoidum, the thin extension at the leading edge of a motile cell, there is a dense actin network composed of branched filaments. That network organizes into regular patterns near the membrane and serves as an engine moving the membrane forward. There are good models explaining how an individual actin filament is able to generate force against a load, but it is not well
understood how filament networks collectively generate force. Multiple patterns have been observed in the force-velocity relationships of actin networks. The first part of this dissertation uses a agent-based stochastic to attempt to explain those patterns. We find that the rate of filament turnover can determine the nature of the force-velocity relationship.

Electron micrographs of actin networks have shown surprisingly regular patterns in the angle of filaments to the membrane. Several continuum models have been proposed to explain this regularity. In the second part of this work, those models are mathematically studied. It has been hypothesized, with numerical evidence, that the equations select for some small number of optimal orientation patterns. The results in chapter 3 imply that both orientation models uniquely select for an optimal orientation pattern. Also, a fitness function for each orientation pattern is derived.

A number of properties of actin filaments have been studied by using atomistic models of actin monomers and filaments. In order to calculate statistical properties of these models, the conformational space needs to be effectively sampled. Current computing capabilities are unable to do so directly, so some form of enhanced sampling algorithm is needed. However, there is no standard way to compare existing methods nor test new methods. The last part of this
dissertation proposes a model that would allow for standardized testing of a large class of enhanced sampling methods.


Social Networking:
Share |


Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairRubin, Jonjonrubin@pitt.eduJONRUBIN
Committee CoChairSwigon, Davidswigon@pitt.eduSWIGON
Committee MemberErmentrout, Bardbard@pitt.eduBARD
Committee MemberMichael, Grabemdgrabe@pitt.eduMDGRABE
Committee MemberJian,
Date: 30 January 2013
Date Type: Publication
Defense Date: 13 August 2012
Approval Date: 30 January 2013
Submission Date: 11 July 2012
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Number of Pages: 140
Institution: University of Pittsburgh
Schools and Programs: Dietrich School of Arts and Sciences > Mathematics
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: Actin
Date Deposited: 30 Jan 2013 17:14
Last Modified: 15 Nov 2016 14:06

Available Versions of this Item

  • Mathematical models of branching actin networks: Results and methods. (deposited 30 Jan 2013 17:14) [Currently Displayed]


Monthly Views for the past 3 years

Plum Analytics

Actions (login required)

View Item View Item