Discovery of nanotubes offers new clues about cell-to-cell communication

July 1, 2015, University of Michigan
Discovery of nanotubes offers new clues about cell-to-cell communication. Credit: Mayu Inaba, University of Michigan

When it comes to communicating with each other, some cells may be more "old school" than was previously thought.

Certain types of stem cells use microscopic, threadlike nanotubes to communicate with neighboring cells, like a landline phone connection, rather than sending a broadcast signal, researchers at University of Michigan Life Sciences Institute and University of Texas Southwestern Medical Center have discovered.

The findings, which are scheduled for online publication July 1 in Nature, offer new insights on how stem cells retain their identities when they divide to split off a new, specialized cell.

The fruit-fly research also suggests that short-range, cell-to-cell communication may rely on this type of direct connection more than was previously understood, said co-senior author Yukiko Yamashita, a U-M developmental biologist whose lab is located at the Life Sciences Institute.

"There are trillions of cells in the human body, but nowhere near that number of signaling pathways," she said. "There's a lot we don't know about how the right cells get just the right messages to the right recipients at the right time."

The nanotubes had actually been hiding in plain sight.

The investigation began when a postdoctoral researcher in Yamashita's lab, Mayu Inaba, approached her mentor with questions about tiny threads of connection she noticed in an image of fruit fly reproductive stem cells, which are also known as germ line cells. The projections linked individual stem cells back to a central hub in the stem cell "niche." Niches create a supportive environment for stem cells and help direct their activity.

Yamashita, a Howard Hughes Medical Institute investigator, MacArthur Fellow and an associate professor at the U-M Medical School, looked through her old image files and discovered that the connections appeared in numerous images.

"I had seen them, but I wasn't seeing them," Yamashita said. "They were like a little piece of dust on an otherwise normal picture. After we presented our findings at meetings, other scientists who work with the same cells would say, 'We see them now, too.'"

It's not surprising that the minute structures went overlooked for so long. Each one is about 3 micrometers long; by comparison, a piece of paper is 100 micrometers thick.

While the study looked specifically at in male Drosophila fruit flies, there have been indications of similar structures in other contexts, including , Yamashita said.

Fruit flies are an important model for this type of investigation, she added. If one was to start instead with , one might find something, but the system's greater complexity would make it far more difficult to tease apart the underlying mechanisms.

The findings shed new light on a key attribute of stem cells: their ability to make new specialized cells while still retaining their identity as stem cells.

Germ line stem cells typically divide asymmetrically. In the male fruit fly, when a stem cell divides, one part stays attached to the hub and remains a stem cell. The other part moves away from the hub and begins differentiation into a fly sperm cell.

Until the discovery of the nanotubes, scientists had been puzzled as to how cellular signals guiding identity could act on one of the cells but not the other, said collaborator Michael Buszczak, an associate professor of molecular biology at UT Southwestern, who shares corresponding authorship of the paper and currently co-mentors Inaba with Yamashita.

The researchers conducted experiments that showed disruption of nanotube formation compromised the ability of the germ line to renew themselves.

Explore further: Divide and define: Clues to understanding how stem cells produce different kinds of cells

More information: Nanotubes mediate niche–stem-cell signalling in the Drosophila testis, Nature, DOI: 10.1038/nature14602

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JVK
1 / 5 (4) Jul 01, 2015
Re: The projections linked individual stem cells back to a central hub in the stem cell "niche." Niches create a supportive environment for stem cells and help direct their activity.

My comment: Niche construction links nutrient-dependent RNA-mediated cell type differentiation to the pheromone-controlled physiology of reproduction in flies.

Niches do not create themselves, which means they cannot create a supportive environment for stem cells or help to direct their activity.

Nothing is created In the absence of the biophysically constrained chemistry of nutrient-dependent protein folding and fixation of RNA-mediated amino acid substitutions that enables cell type differentiation in all cells of all individuals of all genera.

For comparison, see:http://www.ncbi.n...24693353
THIS MODEL DETAILS HOW CHEMICAL ECOLOGY DRIVES: (1) ecological (2) social (3) neurogenic and (4) socio-cognitive niche construction.
Captain Stumpy
3.7 / 5 (3) Jul 01, 2015
For comparison, see:http://www.ncbi.n...24693353
this model has been debunked with actual known validated science

see here:
http://www.socioa...ew/24367
EXCERPT
A multitude of misconceptions and misunderstandings can be seen in his comments on Dr. PZ Myers' blog, Pharyngula (Kohl, 2014b). For example, in comment #125, Kohl says that proteasomes mediate protein folding. Proteasomes do no such thing. They are actually structures whose function is to break down proteins. In that same post, he reiterates his lack of knowledge of natural selection by asking another commenter to 'indicate how a beneficial mutation somehow knew it would be beneficial'.

Based on his writings, both published and unpublished, James Kohl presents an unsupported challenge to modern evolutionary theory and misrepresentations of established scientific terms and others' research.
JVK
1 / 5 (2) Jul 02, 2015
My model has been supported by all the experimental evidence of biologically-based cause and effect that has been published by serious scientists during the past two decades.

See: http://rna-mediat...earning/

Biologically uninformed science idiots are among those who refuse to accept the entirety of evidence that does not support the ridiculous claims of theorists. SSgt James Stumpy (aka Captain Stumpy) appears to be their representative.

Re:
he reiterates his lack of knowledge of natural selection


Natural selection was removed from consideration by the author of "Mutation-Driven Evolution." See also: http://www.scient...plexity/

"Others maintain that as random mutations arise, complexity emerges as a side effect, even without natural selection to help it along. Complexity, they say, is not purely the result of millions of years of fine-tuning..."
Captain Stumpy
3 / 5 (2) Jul 02, 2015

See: http://rna-mediat...earning/
PHISHING SITE PROMOTING CREATIONIST IDEALS ALONG SIDE SCIENCE
this is PSEUDOSCIENCE - NOT SCIENCE
reported
... Stumpy (aka Captain Stumpy) appears to be their representative
right along with PS Myers, Lenski, Extavour, Whittaker and almost EVERY logical and non-religious tainted biologist/medical professional in the USA... at least i am in good company and can understand what is written

like Jones said
In that same post, he reiterates his lack of knowledge of natural selection by asking another commenter to 'indicate how a beneficial mutation somehow knew it would be beneficial'.

Based on his writings, both published and unpublished, James Kohl presents an unsupported challenge to modern evolutionary theory and misrepresentations of established scientific terms and others' research.
@jk... why did you leave out the rest of that in your quote above?

it was VERY relevant as well as specific to the intent/context!
JVK
1 / 5 (2) Jul 02, 2015
PHISHING SITE PROMOTING CREATIONIST IDEALS ALONG SIDE SCIENCE
this is PSEUDOSCIENCE - NOT SCIENCE


http://dx.doi.org...5.06.014
Excerpt: "...our discovery of a dominant role for life-long histone turn-over establishes a novel paradigm by which the contribution of highly dynamic nucleosomal turnover to neurodevelopmental and neuropsychiatric phenomena can now be studied in diverse animal models.

See also: Every amino acid matters: essential contributions of histone variants to mammalian development and disease http://dx.doi.org.../nrg3673

See also: Nutrient-dependent/pheromone-controlled adaptive evolution: a model. http://www.ncbi.n...24693353

My 2013 review linked RNA-mediated amino acid substitutions to cell type differentiation via the physiology of reproduction in species from microbes to man. It was base on what we detailed in the context of molecular epigenetics in our 1996 Hormones and Behavior review article.
Captain Stumpy
5 / 5 (1) Jul 03, 2015
See also: Nutrient-dependent/pheromone-controlled adaptive evolution: a model
see also: Criticisms of the nutrient-dependent pheromone-controlled evolutionary model - Andrew Jones, BA (an actual educated biologist who destroys the kohl creationist pseudoscience)
http://www.socioa...ew/24367

http://dx.doi.org...5.06.014
see also
... H3.3-containing nucleosomes remain highly dynamic—in a modification-independent manner—to control neuronal- and glial-specific gene expression patterns throughout life. Manipulating H3.3 dynamics in both embryonic and adult neurons confirmed its essential role in neuronal plasticity and cognition. Our findings establish histone turnover as a critical and previously undocumented regulator of cell type-specific transcription and plasticity in mammalian brain.
so far, your interpretations are still 100% WRONG

Captain Stumpy
5 / 5 (1) Jul 03, 2015
My 2013 review linked...
but your continued posts here also claim to have linked the speed of light to the de novo creation of amino acids...

your continued posts here also state mutations perturb protein folding, despite the experimental evidence (validated multiple times through various other experiments)
See: Lenski, Dr's Extavour and Whittaker, etc

Your continued posts also claim that your personal rna DOT COM site is science, yet the site itself has posts/links which promote creationist tenets and claims... mixing creationist dogma with science is simply a means to justify your religion, it is NOT SCIENCE - there is no science in the creationist movement - this is obvious: see https://en.wikipe...Arkansas

you also demonstrate cherry-picking above which explains your own personal delusional approach to interpreting science

epic failure
JVK
1 / 5 (1) Jul 03, 2015
http://rna-mediated.com/ and http://perfumingthemind.com/ extend the details we published in the molecular epigenetics section of our 1996 Hormones and Behavior review via what is currently known about the biophysically constrained chemistry of nutrient-dependent protein folding.

In the past two decades, there has been an epic failure by evolutionary theorists to address any aspect of what has been integrated by serious scientists who understand the fact that physics, chemistry, and the conserved molecular mechanisms of cell type differentiation must be linked by experimental evidence of biologically-based cause and effect.

http://www.hawaii...ion.html

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