[BIC-announce] Seminar in Biomedical Engineering - Wednesday Feb 26th - 1h pm - Room 333

[Christophe Grova]

Dear all, 

We will have our next  Biomedical Engineering seminar today

Wednesday  ­ Feb 26th,  at 1 pm

Location: Room  333 Lyman Duff Building (Biomedical Engineering Dpt, 3775
University Street).

Speaker:  Dr. Adam Hendricks PhD Assistant Professor, Department of
Bioengineering, McGill University

Dr. Hendricks is candidate for associate membership in Biomedical
Engineering department, so attendance from our staff members and their
students is highly encouraged.


Title: 
"Coordination of motor protein ensembles in intracellular transport"


Abstract:
The microtubule motors kinesin and dynein function collectively to drive
vesicular transport. These motors navigate complex cytoskeletal networks
through the crowded cellular environment. Using in vitro reconstitution of
vesicle motility, sub-pixel tracking, and optical trapping in living cells,
we find that cargoes are driven by teams of several kinesin and dynein
motors. Consistent with a stochastic tug-of-war mechanism, isolated vesicles
exhibit bidirectional transport in vitro in the absence of external
regulation. We examined the forces exerted on latex bead-containing
phagosomes in living cells, and found the forces exerted by kinesin-1 and
kinesin-2 are indicative of 1-3 motors which often detach at forces below
the unitary stall force of ~6 pN. In contrast, multiple peaks in the dynein
force histogram at 1-2 pN intervals suggest collective transport by many
motors (up to 13). During high-force (|F| > 10 pN) events driven by multiple
motors, the cargoes often advanced in 8-nm steps, suggesting that multiple
kinesin and dynein motors step in a correlated manner at high loads. We
compared forces in living cells to those produced by isolated latex
bead-containing phagosomes along taxol-stabilized microtubules. The force
histograms display similar peaks, indicating that individual motors produce
similar forces in vitro and in living cells. However, forces up to ~ +/-20
pN were observed in living cells compared to maximum forces of ~ +/-12 pN in
vitro, suggesting that for the same type of cargo, more motors are engaged
in the cell. The dense and viscoelastic cellular environment may promote
motor binding by constraining diffusion, or by allowing motors on a single
cargo to interact with multiple microtubules.
   


A list of upcoming seminars can be found at :
http://www.mcgill.ca/bme/news/seminars

See you there 

 
Christophe Grova 

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Christophe Grova, PhD
Assistant Professor
Biomedical Engineering Dpt
Neurology and Neurosurgery Dpt
 
Multimodal Functional Imaging Lab (Multi FunkIm)
Montreal Neurological Institute
Centre de Recherches en Mathématiques
 
Biomedical Engineering Department - Room 304
McGill University
3775 University Street, Montreal, Quebec, Canada,
H3A 2B4 
email : christophe.grova at mcgill.ca <mailto:christophe.grova at mcgill.ca>
tel : (514) 398 2516
fax : (514) 398 7461
 
Web:
http://www.bic.mni.mcgill.ca/ResearchLabsMFIL/PeopleChristophe
http://www.bmed.mcgill.ca/
MultiFunkIm Lab:
http://www.bic.mni.mcgill.ca/ResearchLabsMFIL/HomePage
 
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