When I was a grad student, eukaryotes had all the neatest toys ... actin, microtubules, kinesins, dynein, myosin, dynamin, SNAREs ...
OK that's not totally true - bacteria had their version of tubulin (the constituent of microtubules), and it's called FtsZ. Then others found that bacteria had a version of actin, the most known is called MreB. The latest is that prokaryotes have dynamin. (Click here for previous dynamin entries.)
From the paper:
Given the presence of large GTPases with predicted dynamin-like domain organization in many members of the Eubacteria such as E. coli and Bacillus subtilis, it is likely that bacterial dynamins, or BDLPs as we term this class, are not restricted to cyanobacteria. Such observation, combined with our results, suggests a bacterial ancestry for the dynamin superfamily.
And yes, it forms radial tubes in vitro.
And yes, it also it tubulates membranes in vitro.
And yes, they have a crystal structure.
And yes, it's totally cool.
PS: What's next? Will we find that proks have membrane trafficking?
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Well in a way they do have membrane trafficking. We work on magnetosome organelles which have their own unique set of proteins. There are also other membranous organelles in bacteria that are likely to have their own subset of proteins.
Magnetman thanks for bringing that up. I've written about magnetosomes in the past and they're really neat.
If you look at the IF (or GFP?) images in the paper, BDLP form puncta reminiscent of clathrin coated pits. Most probably the dynamins are responsible for some sort of gross membrane fission and fusion as in mitochondria and chloroplasts (the later being related to the cyanobacteria used in this study). But perhaps there is more membrane trafficking in proks than we currently think and as you suggest magnetosomes may be representative of this.
This is another great story from Jan Lowe's lab. Bacteria are amazing. I still would argue that magnetosomes aren't true organelle but that is just symantics.
Alex, I know about that post, that's how I found your blog and became a regular reader.
BTM, they are not vesicles and have an opening to the periplasm (but so does the nucleus if you want to get technical). but they are membrane enclosed, with unique proteins and have a specified function. In fact the magnetosome membrane exists even in the absence of the magnetite crystals that it produces. The only reason to not call them organelles is that they are not eukaryotic. But then again some eukaryotes have magnetosome-like structures. And some prokaryotes (like the Planctomycetes) seem to ahve a true nuclear membrane.
Magnetman, no worries, I know it is a delicate semantics game that is played here. For years ribosomes were considered organelles. I'm curious where you do your research.
BTM, I'm at Berkeley now.
Ahh, you have given yourself away. You would be the expert in this I suppose so I'll defer to your experience. I have discussed this story with the other authors on the recent work which is where I get my perspective. Great stuff.