From ScienceDaily:
Mitochondria, which exist within human cells but have their own DNA, need many different proteins to function — but the process of how they get these has never been imaged in detail.
Now a study led by Dr Vicki Gold, of the University of Exeter, has shown that some ribosomes — the tiny factories of cells which produce proteins — are attached to mitochondria. This can explain how proteins are pushed into mitochondria whilst they are being made.
The findings open new avenues for studying protein targeting and mitochondrial dysfunction, which has been implicated in diseases including cancer and neurodegenerative disorders such as Parkinson’s.
“Proteins are responsible for nearly all cellular processes. The cell has to make a huge variety of proteins and target them to the precise location where they are needed to function,” said Dr Gold, of Exeter’s Living Systems Institute. Paper. (public access) – Vicki AM Gold, Piotr Chroscicki, Piotr Bragoszewski, Agnieszka Chacinska. Visualization of cytosolic ribosomes on the surface of mitochondria by electron cryo tomography. EMBO reports, 2017; e201744261 DOI: 10.15252/embr.201744261 More.
It all just happened of course, the way every problem in the world accidentally solves itself.
See also: How much evolution can symbiosis account for?
Fascinating. It takes too much faith for me to believe that these highly improbable events happened as a result of random variations, natural selection, and genetic drift. It takes a tremendous amount of faith to be an a/mat.
It was always a question for me as to how mitochondria could have their own ‘genetic code,’ and still be using the cell’s ribosomes for protein production. This study’s conclusion that the mitochondria have their own ribosomes makes muchmore sense.
Of course, for a cell to have ‘two’ ribosomes, each being incredibly complex informational processing units, only makes the task of identifying a plausible Darwinian/neo-Darwinian/neutral drift explanation all the more difficult.
But there are ‘true believers’ out there.
After looking at the PR from Science Daily, I see that the ribosomes are ‘attached,’ and not contained within. As to my earlier post, the need for an explanation of ‘two’ ribosomes will only arise if they find that the ribosomes are duplicated in tandem with the mitochondria: i.e., if they are simply some specialized ‘cell’ ribosome, or, rather, a proper complement of the mitochondria itself. I favor the latter, and not the former possibility.
… but what about midichlorians?
“[…] the importance of recruiting RNA molecules coding for mitochondrial proteins to the outer membrane and their localized translation is likely enhanced in specific cell types and developmental stages of higher eukaryotes.”
This article is about ribosomes on the surface of mitochondria. When did scientists first learn that there was DNA and ribosomes inside the mitochondria?
> It all just happened of course, the way every problem in the world accidentally solves itself.
🙂
Swift had it right. And so ad infinitum.