Scientists reveal structure of nuclear pore's inner ring

April 15, 2016, European Molecular Biology Laboratory
The architecture of the nuclear pore. The outer ring is colored in orange and blue, whereas the newly characterized inner ring is seen in green and lemon. Credit: Jan Kosinski/EMBL

It was a 3D puzzle with over 1000 pieces, with only a rather fuzzy outline as a guide. But scientists at EMBL have now put enough pieces in place to see the big picture. In a study published today in Science, they present their latest findings, bringing the nuclear pore complex into focus.

The nuclear pore is a passage into the cell's nucleus. A typical cell has hundreds of these pores, playing a crucial role in controlling the hundred of thousands of molecules that enter and exit this compartment every minute. Nuclear pores are used by many viruses to inject their genetic material into a host and they are known to change when cells become cancerous, so knowing how they work is important. Scientists understood many of the components of the nuclear pore, but exactly how those building blocks fitted together was unclear.

"The nuclear pore is the biggest, most complicated protein complex in a human cell. We now understand how it is structured," says Martin Beck, who led the work at EMBL. "This is a very important first step towards understanding what actually happens to nuclear pores in cancer, during ageing, and in other conditions."

The nuclear pore is composed of three layered rings: a nuclear ring facing the nucleus; a cytoplasmic ring facing the rest of the cell; and an inner ring in between those two. Having already pieced together how the building blocks of the nuclear and cytoplasmic rings are arranged, Martin Beck's group at EMBL have now worked out the arrangement of the pieces that form the inner ring.

The architecture of the nuclear pore. Repeating protein-protein interaction motifs (green and red) are organised in repeating units (orange, light blue and green and lemon) that form duplicate rings on both the outer and the inner rings. Credit: Jan Kosinski/EMBL
"Surprisingly, we found that although it is made of different , the inner ring has the same basic architecture as the other two rings," says Shyamal Mosalaganti from EMBL, who studied the ring using cryo-electron microscopy. "This very complicated structure is built using simple principles . We were able to uncover that because we interweaved a lot of different techniques here."

Beck and colleagues would now like to understand how the cell completes this 3D puzzle: how the nuclear pore is assembled. Thanks to an ERC grant, the scientists are also exploring how the pore varies between different kinds of cells.

"Knowing this structure, we can now look at how evolved, right at the beginning of the development of complex cells," says Jan Kosinski from EMBL, who put the pieces together using computer modelling. "The moment you have a nucleus—a compartment which encloses DNA—you need a nuclear pore, but how it developed is still the subject of intense debate."

Explore further: Nuclear pore complex successfully mapped and diagramed

More information: J. Kosinski et al. Molecular architecture of the inner ring scaffold of the human nuclear pore complex, Science (2016). DOI: 10.1126/science.aaf0643

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mvg
1 / 5 (1) Apr 15, 2016
"The moment you have a nucleus—a compartment which encloses DNA—you need a nuclear pore, but how it developed is still the subject of intense debate."

blind evolution??
or
the guiding hand of the Creator?
Protoplasmix
5 / 5 (1) Apr 15, 2016
or
the atemporal geometric resolution in a spatiotemporal continuum of scale-dependent quantum mechanical phenomena?
baudrunner
5 / 5 (2) Apr 15, 2016
blind evolution?? or the guiding hand of the Creator?
why blind? There is a quantum logic to the assembly of sub cellular material that these researchers are investigating.

By your own conviction, you are made in his image, so the "creator"'s cells have their own nuclear pores. I'd like you to explain how he assembled himself to create the template that produced the likes of yourself, and, in my opinion, he should run back to the drawing board.
mvg
not rated yet Apr 15, 2016
Protoplasmic--
I really like your word choice!

And baudrunner--
Interesting reasoning--but neither my nor your "convictions" (formulated billions of years after the fact)--have much to do with what really did occur.--That is the SIMULTANEOUS emergence of the cell, the nucleus, AND the pores.----As they say--"You can't have one without the other" .

As to "quantum logic"--logic implies a mind--perhaps THE MIND?

And neither can we say that ANYTHING can happen if we have enough time--since this combination occurred VERY early on.

I suppose one could call upon the "multiverse solution"---but on the basis of that, ANYTHING becomes not only possible but also probable.(INCLUDING the premise that this is the one --or one of many-- universes in which life was guided by the hand of a Creator.)
Jaeherys
not rated yet Apr 18, 2016
mvg:

"The moment you have a nucleus— ... —you need a nuclear pore" is a poorly (I word argue wrong) conceptualized statement. It's like saying, "The moment you have a car, you need a gas peddle." In reality, early cars did not have a gas peddle but clunkier levers to change the throttle. Likewise, early nuclear compartments would most likely have been much simpler and perhaps permeable to RNA. The evolution of nuclear pores would most likely have followed a need for greater control of increasingly complex gene expression.

The simultaneous emergence of a complex cell is very, very, VERY improbable. As of right now, nothing would suggest this, not even the Abrahamic religions. Even if you literally believe in Adam and Eve, Homo sapiens and all other life on Earth already existed. What happened was the intermingling of their DNA with other Homo sapiens. There is no evidence to suggest this happened but that is why it is faith and not observation.

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