In my journey to becoming #50, I learned two lessons in flexibility: one was in what I study, mic... more In my journey to becoming #50, I learned two lessons in flexibility: one was in what I study, microtubule mechanics, and the other was in life. I will tell you the story of my path to becoming the 50th African American woman to earn a PHD in physics in the US, discuss why there are still fewer than 100, and how we can change this number. I will also chat about my research in microtubule mechanics
2020 IEEE 15th International Conference on Nano/Micro Engineered and Molecular System (NEMS), 2020
Microtubules (MTs) are highly dynamic tubular biopolymers, involving in many cellular processes s... more Microtubules (MTs) are highly dynamic tubular biopolymers, involving in many cellular processes such as intracellular transport, cellular structure maintenance, and cell division. All the processes require that MTs have adequate and adjustable flexural rigidity to cope with different functions. Despite the importance of MT mechanics, previously reported values of MTs’ flexural rigidity vary significantly. Here we provide an explanation for such a longstanding discrepancy. Moreover, with the localization precision optimized to the nanometer-level, we find that the flexural rigidity of MTs is dependent on growth rate. Not only do our results show the importance of localization precision on flexural rigidity studies, but also highlight the significance of the MT growth rate.
Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tenness... more Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.
Microtubules are biopolymers that perform diverse cellular functions. The regulation of microtubu... more Microtubules are biopolymers that perform diverse cellular functions. The regulation of microtubule behavior occurs in part through post-translational modification of both the α- and β- 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 α-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 (R2) showed a pronounced...
Kinesin-driven microtubules have been a focus to serve as molecular shuttles to replace multiple ... more Kinesin-driven microtubules have been a focus to serve as molecular shuttles to replace multiple on-chip functions in micro total analysis systems (μTAS). Although transport, concentration, and detection of target molecules have been demonstrated, controllability of transport directions is still a major challenge. To define multiple moving directions for selective molecular transport, we integrated the bottom-up molecular design of microtubules and the top-down design of a microfluidic device. The surface charge density and stiffness of microtubules were controlled, allowing us to create three different types of microtubules with different gliding directions corresponding to their electrical and mechanical properties. The measured curvature of gliding microtubules enabled us to optimize the size and design of the device for molecular sorting in a top-down approach. The integrated bottom-up and top-down design achieved separation of stiff microtubules from negatively-charged soft mic...
In my journey to becoming #50, I learned two lessons in flexibility: one was in what I study, mic... more In my journey to becoming #50, I learned two lessons in flexibility: one was in what I study, microtubule mechanics, and the other was in life. I will tell you the story of my path to becoming the 50th African American woman to earn a PHD in physics in the US, discuss why there are still fewer than 100, and how we can change this number. I will also chat about my research in microtubule mechanics
2020 IEEE 15th International Conference on Nano/Micro Engineered and Molecular System (NEMS), 2020
Microtubules (MTs) are highly dynamic tubular biopolymers, involving in many cellular processes s... more Microtubules (MTs) are highly dynamic tubular biopolymers, involving in many cellular processes such as intracellular transport, cellular structure maintenance, and cell division. All the processes require that MTs have adequate and adjustable flexural rigidity to cope with different functions. Despite the importance of MT mechanics, previously reported values of MTs’ flexural rigidity vary significantly. Here we provide an explanation for such a longstanding discrepancy. Moreover, with the localization precision optimized to the nanometer-level, we find that the flexural rigidity of MTs is dependent on growth rate. Not only do our results show the importance of localization precision on flexural rigidity studies, but also highlight the significance of the MT growth rate.
Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tenness... more Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.
Microtubules are biopolymers that perform diverse cellular functions. The regulation of microtubu... more Microtubules are biopolymers that perform diverse cellular functions. The regulation of microtubule behavior occurs in part through post-translational modification of both the α- and β- 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 α-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 (R2) showed a pronounced...
Kinesin-driven microtubules have been a focus to serve as molecular shuttles to replace multiple ... more Kinesin-driven microtubules have been a focus to serve as molecular shuttles to replace multiple on-chip functions in micro total analysis systems (μTAS). Although transport, concentration, and detection of target molecules have been demonstrated, controllability of transport directions is still a major challenge. To define multiple moving directions for selective molecular transport, we integrated the bottom-up molecular design of microtubules and the top-down design of a microfluidic device. The surface charge density and stiffness of microtubules were controlled, allowing us to create three different types of microtubules with different gliding directions corresponding to their electrical and mechanical properties. The measured curvature of gliding microtubules enabled us to optimize the size and design of the device for molecular sorting in a top-down approach. The integrated bottom-up and top-down design achieved separation of stiff microtubules from negatively-charged soft mic...
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