Navigation Links
Molecular Motors Cooperate In Moving Cellular Cargo, Study Shows

Researchers using an extremely fast and accurate imaging technique have shed light on the tiny movements of molecular motors that shuttle material within living cells. The motors cooperate in a delicate choreography of steps, rather than engaging in the brute-force tug of war many scientists had imagined.

"We discovered that two molecular motors -- dynein and kinesin -- do not compete for control, even though they want to move the same cargo in opposite directions," said Paul Selvin, a professor of physics at the University of Illinois at Urbana-Champaign and corresponding author of a paper to appear in the journal Science, as part of the Science Express Web site, on April 7. "We also found that multiple motors can work in concert, producing more than 10 times the speed of individual motors measured outside the cell."

Dynein and kinesin are biomolecular motors that haul cargo from one part of a cell to another. Dynein moves material from the cell membrane to the nucleus; kinesin moves material from the cell nucleus to the cell membrane. The little cargo transporters accomplish their task by stepping along filaments called microtubules.

To measure such minuscule motion, Selvin and colleagues at Illinois developed a technique called Fluorescence Imaging with One Nanometer Accuracy. The technique can locate a fluorescent dye to within 1.5 nanometers (one nanometer is a billionth of a meter, or about 10,000 times smaller than the width of a human hair). Recent improvements to FIONA now allow scientists to detect motion with millisecond time resolution.

Selvin's team used FIONA to track fluorescently labeled peroxisomes (organelles that break down toxic substances) inside specially cultured fruit fly cells. This was the first time the imaging technique had been used inside a living cell.

"Our measurements show that both dynein and kinesin carry the peroxisomes in a step-by-step fashion, moving about 8 nanometers per step," said Sel vin, who also is a researcher at the Frederick Seitz Materials Research Laboratory on the Illinois campus.

"Because we see a fairly constant step size, we don't believe a tug of war is occurring," Selvin said. "If the dynein was fighting the kinesin, we would expect to see a lot of smaller steps as well."

The researchers also noted that faster movements occurred with the same step size, but with greater rapidity. When measured outside the cell, kinesin moved about 0.5 microns per second. Inside the cell, the speed increased to 12 microns per second.

"There must be a mechanism that allows the peroxisomes to move by multiple motors much faster than independent, uncoupled kinesins and dyneins," Selvin said. "It appears that motors are somehow regulated, being turned on or off in a fashion that prevents them from simultaneously dragging the peroxisome."

In the future, Selvin wants to combine FIONA and an optical trap technique to monitor the speed and direction of a peroxisome, and the force acting upon it.

"By measuring force we can determine how many molecular motors are working together," Selvin said. "This will help us further understand these marvelous little machines."


'"/>

Source:University of Illinois at Urbana-Champaign


Related biology news :

1. Molecular biology fills gaps in knowledge of bat evolution
2. Molecular machine may lead to new drugs to combat human diseases
3. Molecular models advance the fight against malaria
4. Molecular fossils uncover link between viruses and the immune system
5. Molecular thermometers on skin cells detect heat and camphor
6. Molecular messengers perform a crucial role in the ability of injured nerve cells to heal themselves
7. Molecular steps involved in the creation of gene-silencing microRNAs identified
8. Molecular miners find pain relief drugs from the sea
9. Molecular mechanism of feather formation found
10. Molecular trigger for Huntingtons disease found
11. Molecular Partners Required For Appropriate Neuronal Gene Repression
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:2/1/2016)... YORK , Feb. 1, 2016  Today, the ... Association (AHA) announced plans to develop a first of ... computing power of IBM Watson. In the first application ... AHA, IBM (NYSE: IBM ), and Welltok will ... and health assessments with cognitive analytics, delivered on Welltok,s ...
(Date:1/25/2016)... BLUE BELL, Pa. , Jan. 25, 2016   Unisys ... facial recognition system at John F. Kennedy (JFK) International Airport, ... and Border Protection (CBP) identify imposters attempting to enter ... or do not belong to them. pilot testing ... rolled out initially at three terminals at JFK during January 2016. ...
(Date:1/21/2016)... , January 21, 2016 ... a new market research report "Emotion Detection and Recognition ... Software Tools (Facial Expression, Voice Recognition and Others), ... Global forecast to 2020", published by MarketsandMarkets, the ... to reach USD 22.65 Billion by 2020, at ...
Breaking Biology News(10 mins):
(Date:2/8/2016)... FREDERICK, Md. , Feb. 8, 2016 /PRNewswire/ ... advanced consumer medical devices, announced today that it ... for administrative proceedings from the Securities and Exchange ... Richard Staelin , Chairman of the Board ... Donnell Professor of Business Administration at The Fuqua ...
(Date:2/8/2016)... (PRWEB) , ... February 08, 2016 , ... ... a wide range of loose, bulk foods at various stages of the production ... also used to inspect large bulk products post packaging such as sacks of ...
(Date:2/8/2016)... Inc. (NYSE MKT: NNVC) (the "Company"), a nanomedicine company developing anti-viral ... will present information about the company,s programs at the BIOCEO conference ... York City . --> --> ... EST. Registered attendees can request a one on one meeting through ... --> New York City . ...
(Date:2/8/2016)... Pharmacy, Inc. (NYSE: DPLO) announced today that its new website has gone live. On Thursday, Feb. ... Visit the new site: www.diplomat.is ... ... ... "The goal was to reimagine the website and create a ...
Breaking Biology Technology: