Steven Markus Assistant Professor

Office: Mrb 241

Phone: (970) 491-5979

Website: http:\\


  • Ph.D., New York University Medical Center


Our laboratory is focused on understanding the mechanisms regulating motor-based transport in cells, with a particular focus during mitosis. A fundamental and critical aspect of eukaryotic cells is their complex and well-defined internal organization. This high level of internal organization is achieved in large part by the well orchestrated motor-mediated delivery of various cargo to appropriate sites within the cell. The microtubule motors dynein and kinesin mediate the directional transport of cellular cargo (including the mitotic spindle) in the minus and plus end direction, respectively (i.e., toward the cell center, and the cell periphery, respectively). How these motors are regulated to carry out their respective functions is a central question in cell biology. We have recently identified a microtubule associated protein, She1, as a molecule with the ability to differentially affect the motility of dynein and kinesin. How this molecule achieves its motor specificity, and how this molecule is regulated within cells is unclear, and is one of the focuses of our laboratory. Techniques utilized by our lab include fluorescent microscopy (traditional wide-field, confocal, and total internal reflection fluorescence (TIRF) microscopy), genetics, biochemistry and various molecular biological approaches. For instance, using TIRF microscopy, we can watch single molecules of molecular motors walking along their respective tracks (see movies below). We expect that our findings will have implications for basic cellular biology, and also for understanding the pathogenesis of various disease states. For instance, aneuploidy (improper chromosome number) and tumor initiation correlate with defects in dynein mediated spindle positioning during cell division.  


Cool Movies: Click on the following links to watch movies acquired using time-lapse fluorescence microscopy. Each movie shows examples of purified molecular motors walking along microtubule tracks.

Human Kinesin-1 motors walking.

Yeast Kip2 motors walking.

Yeast Dynein (red) and Kip2 (green) motors walking.


Modeling disease-correlated TUBA1A mutation in budding yeast tubulin reveals a molecular basis for tubulin dysfunction.E. Dénarier, Kari Hope Ecklund, G. Berthier, M. Poitevin, A. Favier, S. Gory, C. Delphin, A. Andrieux, Steven M. Markus, Cécile Boscheron n/a.
She1 coordinates dynein-mediated spindle positioning by spatially restricting dynein activity in yeast.Kari Hope Ecklund, Megan Bailey, Jordan Rivera, Kelly Kossen, Carsten Jacobus Dietvorst, Charles Asbury, Steven M. Markus n/a.
Zinc is a key effector of neuronal health by modulating axonal transport.Dylan Fudge, Matthew George Marzo, Steven M. Markus, Yan Qin n/a.
Pac1/LIS1 stabilizes an uninhibited conformation of dynein to coordinate its localization and activityMatthew George Marzo, Griswold M. Jacqueline, Steven M. Markus Nature Cell Biology.
Molecular Basis for Dyneinopathies Reveals Insight Into Dynein Regulation and DysfunctionMatthew George Marzo, Jacqueline M. Jacqueline, Kristina M. Ruff, Rachel Emily Buchmeier, Fees Colby, Steven M. Markus Elife, 2019.
Effectors of the Spindle Assembly Checkpoint Are Confined Within the Nucleus of Saccharomyces CerevisiaeLydia Rene Heasley, Jennifer G. DeLuca, Steven M. Markus Biology Open, 6, 2019.
She1 affects dynein through direct interactions with the microtubule and the dynein microtubule-binding domainKari Hope Ecklund, Tatsuya Morisaki, Lindsay G. Lammers, Matthew George Marzo, Tim John Stasevich, Steven M. Markus Nature Communications, 1, 2017.
'Wait Anaphase' Signals Are Not Confined to the Mitotic SpindleLydia Rene Heasley, Steven M. Markus, Jennifer G. DeLuca Molecular Biology of the Cell, 2017.
Improved Plasmids for Fluorescent Protein Tagging of Microtubules in Saccharomyces cerevisiaeSteven M. Markus, Safia Omer, Kaitlyn Baranowski, Wei-Lih Lee Traffic, 2015.
The dynein cortical anchor Num1 activates dynein motility by relieving Pac1/LIS1-mediated inhibitionLindsay G. Lammers, Steven M. Markus The Journal of cell biology, 2, 2015.
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