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originally posted by: whereislogic
a reply to: soficrow
Explain what I don't understand ...
One-celled life possessed tools for going multicellular
Scaling up from one cell to many may have been a small step rather than a giant leap for early life on Earth. …
“Animals are regarded as this very special branch, as in, there had to be so many innovations to be an animal,” says David Booth, a biologist at the University of California, Berkeley who wasn’t part of the study. But this research shows “a lot of the machinery was there millions of years before animals evolved.”
...That parallels what’s seen in animals: Proteins in different organs within the same animal show similar modification differences.
The researchers also found changes in the molecules that control the protein modification process. ...
...the perceived chasm between a simple single-celled existence and a complex multicellular one might not have required a flying leap to cross. “This gap,” Sabidó says, “maybe isn’t such a gap.”
originally posted by: richapau
a reply to: soficrow
It is more accurate to say instead of "Inheritance is protein-based - it’s epigenetic, not genetic. " Inheritance can also be protein based. This new knowledge doesn't change the fact that genetic ( DNA) mutation is also a method of heritable trait transmission.
posted by whereislogic
What may also help is understanding what prions actually are and what they do to an organism (in reality, not imagination/La La Land/fancy speculation/'in the eye of the beholder'-spin, using preferences or philosophical bias in how things are phrased): [/url]
The Scientist, 2014: The Bright Side of Prions
Associated with numerous neurological diseases, misfolded proteins may also play decisive roles in normal cellular functioning.
Stanford Medicine 2016: Prions can pass on beneficial traits, study finds
Researchers have found nearly 50 helpful prions in yeast and comparable proteins in humans, suggesting that this dreaded protein type can boost survival and plays a role in evolution.
originally posted by: soficrow
a reply to: raymundoko
For example, whereislogic insists that prions by definition can only cause disease,
Focus on the quotation that combines "in their native conformations" with suggesting that they're talking about "prion proteins" (in their native conformation apparently).
Why do they refer to proteins in their native conformation as prion proteins (also remember the terminology I quoted earlier "native nonprion conformation")? But elsewhere others define prion proteins as misfolded proteins (i.e. not in their native conformation)?
Is it possible to get a straight answer from those doing the above for motives that I have alluded to (perhaps a bit too cryptically)?
(soficrow said, “whereislogic insists that prions by definition can only cause disease”) Never said such a thing.
Why do they refer to proteins in their native conformation as prion proteins …?
But elsewhere others define prion proteins as misfolded proteins (i.e. not in their native conformation)?
Third, for prion that are inactive forms of a normally active protein,...
Thank you for telling me things I already learned…
1st page, OP, 2nd paragraph:
“Specifically, prions, aka “intrinsically disordered proteins” that can “pass heritable traits from cell to cell by their structure instead of by DNA.” ”
Two studies describe the function of PrPc, the 'good' alter ego of prions
Two new studies coordinated by SISSA reveal important details about the physiological function of the prion protein, the non-pathological form of the notorious prion, the degenerate protein responsible for several diseases including "mad cow disease." According to the new findings, the protein in its physiological form serves the important function of promoting the growth of neurites, the neural projections along which nerve impulses travel. The two studies ideally complement each other in that one, published in the Journal of Cell Science, provides a general overview and the other, published in the Journal of Biological Chemistry, focuses on a specific stage in the process, which it describes with unprecedented completeness and detail.
The prion protein has two diametrically opposed faces: sadly notorious for its "degenerate" form that causes severe and incurable neurodegenerative diseases such as "mad cow disease" in cattle and Creutzfeldt-Jakob syndrome in humans, in its physiological form the prion protein (PrPC) serves a vital function for the brain. Its positive action had, however, never been clarified until now. Two new studies, both coordinated by Giuseppe Legname, professor at the International School for Advanced Studies (SISSA) in Trieste, finally provide a detailed description of the biochemical processes through which this protein stimulates and guides the growth of neurites, the neural membrane projections (axons and dendrites) that are all important for the conduction of nerve signals.
Characterization of prion protein function by focal neurite stimulation
The cellular prion protein (PrPC), encoded by the PRNP gene, is a ubiquitous glycoprotein, which is highly expressed in the brain. This protein, mainly known for its role in neurodegenerative diseases, is involved in several physiological processes including neurite outgrowth. By using a novel focal stimulation technique, we explored the potential function of PrPC, in its soluble form, as a signaling molecule. Thus, soluble recombinant prion proteins (recPrP) encapsulated in micro-vesicles were released by photolysis near the hippocampal growth cones. Local stimulation of wild-type growth cones with full-length recPrP induced neurite outgrowth and rapid growth cone turning towards the source. This effect was shown to be concentration dependent. Notably, PrPC-knockout growth cones were insensitive to recPrP stimulation, but this property was rescued in PrP-knockout growth cones expressing GFP–PrP. Taken together, our findings indicate that recPrP functions as a signaling molecule, and that its homophilic interaction with membrane-anchored PrPC might promote neurite outgrowth and facilitate growth cone guidance.