Green plant transport mystery solved

Jan 26, 2010

Contrary to prevailing wisdom, a new study from plant biologists at UC Davis shows that proteins of the Hsp70 family do indeed chaperone proteins across the membranes of chloroplasts, just as they do for other cellular structures.

The findings are published online in the January issue of the journal The .

One of the most crucial tasks in a living cell is to move things across membranes, both in and out of the cell and between different compartments inside.

Chloroplasts are structures inside the cells of green plants that carry out . Like , which generate energy for the cell, chloroplasts are thought to be descended from a free-living organism that took up residence in an ancestral cell, bringing photosynthesis with it.

Hsp70s are known to act as 'chaperones' that escort proteins across membranes within cells, including mitochondria. But Hsp70 did not appear to work in the same way in chloroplasts, where a different protein called Hsp93 seemed to fill the chaperone role.

Research scientist Lan-Xin Shi and Steven Theg, professor of , used the moss Physcomitrella patens to study the Hsp70 proteins in chloroplasts. Unusually for a plant, Physcomitrella repairs its DNA in such a way that specific can be selectively "knocked out," much as they can be in a laboratory mouse.

Shi and Theg found four genes that encode chloroplast Hsp70s in the moss. Knocking out one of these genes, Hsp70-2, killed the plant. Moreover, reducing protein levels of Hsp70-2 resulted in reduced protein import into isolated chloroplasts.

The results show that principles used in the transport machineries of chloroplasts, mitochondria and other cellular bodies have been conserved through evolution, Theg said.

"I always wondered why it was different in chloroplasts," Theg said. "This opens the possibility that the mechanism works the same way in all these cases."

Explore further: The malaria pathogen's cellular skeleton under a super-microscope

Provided by University of California - Davis

4 /5 (1 vote)

Related Stories

Green Plants Share Bacterial Toxin

Nov 06, 2006

A toxin that can make bacterial infections turn deadly is also found in higher plants, researchers at UC Davis, the Marine Biology Laboratory at Woods Hole, Mass. and the University of Nebraska have found. ...

Researchers give mutants another chance

Feb 11, 2009

Researchers at Fox Chase Cancer Center have demonstrated that it might be possible to treat genetic diseases, including some forms of cancer, by "rescuing" the misshapen, useless proteins produced by some mutant genes.

Discovering the secret code behind photosynthesis

Feb 25, 2009

(PhysOrg.com) -- Scientists from Queen Mary, University of London have discovered that an ancient system of communication found in primitive bacteria, may also explain how plants and algae control the process of photosynthesis.

Recommended for you

Researchers successfully clone adult human stem cells

5 hours ago

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

Researchers develop new model of cellular movement

8 hours ago

(Phys.org) —Cell movement plays an important role in a host of biological functions from embryonic development to repairing wounded tissue. It also enables cancer cells to break free from their sites of ...

For resetting circadian rhythms, neural cooperation is key

Apr 17, 2014

Fruit flies are pretty predictable when it comes to scheduling their days, with peaks of activity at dawn and dusk and rest times in between. Now, researchers reporting in the Cell Press journal Cell Reports on April 17th h ...

User comments : 0

More news stories

Researchers successfully clone adult human stem cells

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

Plants with dormant seeds give rise to more species

Seeds that sprout as soon as they're planted may be good news for a garden. But wild plants need to be more careful. In the wild, a plant whose seeds sprouted at the first warm spell or rainy day would risk disaster. More ...

Researchers develop new model of cellular movement

(Phys.org) —Cell movement plays an important role in a host of biological functions from embryonic development to repairing wounded tissue. It also enables cancer cells to break free from their sites of ...

Male monkey filmed caring for dying mate (w/ Video)

(Phys.org) —The incident was captured by Dr Bruna Bezerra and colleagues in the Atlantic Forest in the Northeast of Brazil.  Dr Bezerra is a Research Associate at the University of Bristol and a Professor ...