Profile for Taviare Hawkins

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Specialty area(s)

Computational Methods and Experimental Biophysics

Brief biography

I am a native of Chicago and I spent the first half of my life in the Midwest. I attended the University of Iowa in Iowa City, Iowa, where I received my BS in Physics and a minor in African American Studies. I left the world of academia for 3 year, moved out east to the island of Manhattan. Where I became a Real Estate Asset Manager for the Resolution Trust Corporation. (It really is true that with a physics degree, you can do just about anything!). I then entered graduate school at Syracuse University in Syracuse, New York. There I completed two MS degrees, one in Computer Science and the other in Physics, as well as, a PhD in Physics. My graduate work was in nonlinear systems analysis and human computer interfacing. It was also at Syracuse that I became interested in teaching. I went onto postdoc at the University of Massachusetts-Amherst in an experimental biophysics lab.

I have taught physics at Syracuse University, Xavier University of Louisiana, Mount Holyoke College, and now at the University of Wisconsin-La Crosse. I have more than 9 years of teaching experience. I have taught introductory physics, algebra and calculus based, in the traditional lecture style, as well as, in the more interactive workshop style. I have taught housewives to physics majors, premeds and pre-pharmacy students, as well as graduate students in the Molecular and Cellular Biology department. I have also taught advanced topics like, optics, modern, and advanced laboratory experiment.

Current courses at UWL

PHY 203 - General Physics I (Calculus-based Mechanics taught in the Active-Learning style)
PHY 311 - Experimental Physics Laboratory (Writing emphasis intermediate physics laboratory)
PHY 497 - Physics Seminar
PHY 498 - Physics and Astronomy Research: Experimental Biophysics

Education

Biophysics, University of Massachusetts -Amherst, Amherst Massachusetts (Postdoc)
Physics, Syracuse University, Syracuse, New York (MS & PhD)
Computer Science, Syracuse University, Syracuse, New York ( MS )
Physics, University of Iowa, Iowa City, Iowa ( BS )

Teaching history

PHY 103 Laboratory - Fundamental Physics I (Algebra-based)
PHY 125 - Physics for the Life Sciences (Algebra-based Lecture and Laboratory)
PHY 203 - General Physics I (Calculus-based Mechanics taught in the Active-Learning style)
PHY 204 - General Physics II (Calculus-based Electricity and Magnetism taught in the Active Learning style)
PHY 250 - Modern Physics
PHY 311 - Experimental Physics Laboratory (Writing emphasis intermediate physics laboratory)
PHY 314 - Introduction to Biophysics: Biomechanics and Special Topics in Biophysics
PHY 453 -Topics in Physics & Astronomy: Biophysical Studies of Cellular Processes
PHY 453 - Topics in Physics & Astronomy: Introduction to Scientific Writing in Experimental Biophysics
PHY 453 - Topics in Physics & Astronomy: Advance Experimental Biomechanics
PHY 491 - Physics Capstone
PHY 497 - Physics Seminar
PHY 498 - Physics and Astronomy Research
CHM 499 - Chemistry Research

Professional history

2019 – Present  Chair and Professor of Physics ( 2019)
2016 – 2019  Associate Professor of Physics (Tenured 2018)
2012 – 2016  Assistant Professor of Physics
Department of Physics and Astronomy, University of Wisconsin-La Crosse, La Crosse, WI

2009 – 2012  Postdoctoral Research Associate
Physics Department, University of Massachusetts-Amherst, Amherst, MA

2008 – 2010   Mount Holyoke Fellow and Visiting Assistant Professor
Department of Physics, Mount Holyoke College, South Hadley, MA

Research and publishing

My research involves working on problems that lie at the intersections of physics, mathematics, engineering, biology and chemistry. I am a biophysicist that uses the quantitative skills and methods I learned in physics to gain a better understand how living cells do what they do. Since this problem is very complicated and quite broad, I have focused my attention on the cytoskeletal filaments called microtubules. Understanding the mechanics and dynamics properties of microtubules in addition to how microtubule associated proteins work to fine tune these properties within cells, is the area where my research interests lie.

Selected Publications: 

9. K.P. Wall, H. Hart*, T. Lee, C. Paige, T.L. Hawkins, and L. Hough, "C-terminal tail polyglycylation and polyglutamylation alter microtubule mechanical properties," (Submitted).

8. H. Zhou, N. Isozaki, K. Ukita, T.L. Hawkins, J.L. Ross, and R. Yokokawa, "Nanometer-level localization precision reveals growth rate-dependent flexural rigidity of microtubules,".

7.  (Invited Book Chapter) D.R. Mitchell, T.L. Hawkins, and K.W. Foster, “Chapter 23: Microtubule Based Motility,” Cell Physiology Source Book (Under review).

6.  B.J. Harris*, J.L. Ross, and T.L. Hawkins, “Microtubule seams are not mechanically weak defects,Physical Review E 97 062408 (2018).  doi: 10.1103/PhysRevE.97.062408

5.  N. Isozaki, H. Shintaku, H. Kotera, T.L. Hawkins, J.L. Ross, and R. Yokokawa, “Control of molecular shuttles by designing electrical and mechanical properties of microtubules,” Science Robotics (2017). doi: 10.1126/scirobotics.aan4882

Also published as: "Sorting of molecular shuttles by designing electrical and mechanical properties of microtubules," BioRxiv (2017). doi:https://doi.org/10.1101/107458

4.  M. Bailey, L. Conway, M.W. Gramlich, T.L. Hawkins, J.L. Ross, “Modern Methods to Interrogate Microtubule Dynamics,” Integrative Biology 1324-1333 (2013) Chosen as an iBiology HOT Article!doi: 10.1039/C3IB40124C

3.  T.L. Hawkins, D. Sept, B. Moogessie, A. Straube, J.L. Ross, “Mechanics of Doubly Stabilized Microtubules,” Biophysical Journal 104 1517-1528 (2013). (Cover Art) Chosen for Biophysical Journal Collection on Molecular Motors and the Cytoskeleton! doi: 10.1016/j.bpj.2013.02.026)

2.  T.L. Hawkins, M. Mirigian*, J. Li*, M.S. Yasar, D.L. Sackett, D. Sept, J.L. Ross, “Perturbations in Microtubule Mechanics from Tubulin Preparation,” Cellular and Molecular Bioengineering 5 227-238 (2012).

1.  T. Hawkins, M. Mirigian*, M. Selcuk Yasar, J.L. Ross, “Mechanics of Microtubules,” Journal of Biomechanics 43 23-30 (2010). doi: 10.1016/j.jbiomech.2009.09.005

*Undergraduate Author

Kudos

presented

Harold Hart, Physics '19; Loren Hough, Thomas Lee, Kathryn P. Wall and Cynthia Paige, all University of Colorado Boulder; and Taviare Hawkins, Physics; presented "C-Terminal Tail Polyglycylation and Polyglutamylation alter microtubule Mechanical Properties" at Biophysical Society Annual Meeting on Feb. 19 in San Diego, California Convention Center. Microtubules are biopolymers that perform diverse cellular functions. The regulation of microtubule behavior occurs in part through post-translational modification of both the alpha- and beta- subunits of tubulin. One class of modifications is the heterogeneous addition of glycine and glutamate residues to the disordered C-terminal tails of tubulin. Due to their prevalence in stable, high-stress cellular structures such as cilia, we sought to determine if these modifications alter the intrinsic stiffness of microtubules. Here we describe the purification and characterization of differentially-modified pools of tubulin from Tetrahymena thermophila. We found that glycylation on the alpha-C-terminal tail is a key determinant of microtubule stiffness, but does not affect the number of protofilaments incorporated into microtubules. We measured the dynamics of the tail peptide backbone using nuclear magnetic resonance spectroscopy. We found that the spin-spin relaxation rate showed a pronounced decreased as a function of distance from the tubulin surface for the alpha-tubulin tail, indicating that the alpha-tubulin tail interacts with the dimer surface. This suggests that the interactions of the alpha-C-terminal tail with the tubulin body contributes to the stiffness of the assembled microtubule, providing insight into the mechanism by which glycylation and glutamylation can alter microtubule mechanical properties.

Submitted on: Feb. 24

presented

Taviare Hawkins, Physics, presented " Updates in Microtubule Mechanics" at 2019 Joint Spring Meeting of the APS Ohio-Region Section, Ohio Section of the American Association of Physics Teachers (AAPT) and Zone 7 of the Society of Physics Students (SPS) on April 1, 2019 in Wooster, Ohio. Hawkins gave an invited plenary talk. This year's theme was Frontiers in Nonlinear Science.

Submitted on: April 1, 2019

served

Taviare Hawkins, Physics served as part of a panel discussion on Careers in Education at the American Physical Society (APS) Conferences for Undergraduate Women in Physics (CUWiP). CuWIPs are annual, three-day regional conferences for undergraduate physics majors. The goal of CUWiP is to help undergraduate women continue in physics by providing them with the opportunity to experience a professional conference, information about graduate school and professions in physics, and access to other women in physics of all ages with whom they can share experiences, advice and ideas. This CuWIP was a collaboration between APS and University of Massachusetts, Amherst, as well as, Amherst, Smith, and Mount Holyoke colleges. The event was held over the weekend of Jan. 18 - 20, 2019 at UMass Amherst.

Submitted on: Jan. 25, 2019

presented

Taviare Hawkins, Physics, presented "Adventures in Microtubule Mechanics" at Invited Lehigh Physics Colliquium on Dec. 5, 2018 in Bethlehem, PA. Microtubules, the largest filaments in the cytoskeleton, play an important role in cellular division, intracellular transport, and the structural shape to the cell. Each of these functions requires that microtubules be stiff when forming the scaffolding for the cell and flexible when the cell needs to divide. The mechanics of microtubules has been an active branch of research for both physicists and engineers alike for more than 30 years. However, a consensus has not been reached regarding their measured persistence length. Here we present our experimental results on microtubule mechanics and how persistence lengths may be altered by: purification, labeling, age, salt content, or the presence of microtubule-associated proteins (MAPs) which are typically found in cells. To address these questions, we use the freely fluctuating filament assay, along with the statistics of bootstrapping, to find that combinations of these stabilizers have novel effects on the mechanical properties of microtubules.

Submitted on: Dec. 5, 2018

published

Brandon Harris, Graduate Biology, and Taviare Hawkins, Physics, co-authored the article "Microtubule seams are not mechanically weak defects" in "Physical Review E" published on June 13, 2018 by American Physical Society (APS). Abstract: Microtubule rigidity is important for many cellular functions to support extended structures and rearrange materials within the cell. The arrangement of the tubulin dimers within the microtubule can be altered to affect the protofilament number and the lattice type. Prior electron microscopy measurements have shown that when polymerized in the presence of a high concentration of NaCl, microtubules were more likely to be ten protofilaments with altered intertubulin lattice types. Specifically, such high-salt microtubules have a higher percentage of seam defects. Such seams have long been speculated to be a mechanically weak location in the microtubule lattice, yet no experimental evidence supported this claim. We directly measured the persistence length of freely fluctuating filaments made either with high salt or without. We found that the microtubules made with high salt were more flexible, by a factor of 2, compared to those polymerized the same way without salt present. The reduced persistence length of the high-salt microtubules can be accounted for entirely by a smaller cross-sectional radius of these microtubules, implying that the mixed lattice interactions have little effect on the bending rigidity. Our results suggest that the microtubule seam is not weaker than the typical lattice structure as previously speculated from structural studies.

Submitted on: June 14, 2018