AUG 07, 2016 11:37 AM PDT

Inside bacteria, everything has its place

WRITTEN BY: Kerry Evans
Eukaryotic cells are nicely organized - all the important bits are housed in the nucleus or associated with other organelles. But, what about bacteria? How do they keep everything organized without organelles?

For many years, people assumed that bacteria were just little bags filled with genetic material, proteins, and other molecules. The other assumption was that that all of these components just sloshed about willy-nilly without any strict organizational scheme.
The insides of bacteria stay organized, even without organelles.
It turns out, however, that the innards of bacterial cells are surprisingly well-organized. A short review on the subject was recently authored by Sutharsan Govindarajan and Orna Amster-Choder in Current Opinion in Microbiology.

The cell poles of rod-shaped bacteria are one hub at which proteins accumulate and organize themselves. The poles are particularly important for localizing sensory systems. In E. coli, the receptors for chemotaxis and phosphotransferase (carbon uptake) systems, for example, organize themselves at the cell poles. The fact that both of these systems localize to the same part of the cells means it’s easy for them to communicate with each other - the two systems have to work together to make sure the bacteria find the right nutrients.

In addition to the poles, the protein MreB helps confer an organizational structure to the bacterial cell. MreB is an actin homolog that has been likened to a bacterial cytoskeletal protein, shuttling proteins to and fro.

MreB is attached to the cytoplasmic face of the inner membrane. One of MreB’s jobs in E. coli is to relocate penicllin binding proteins from one part of the cell to another so that they can remodel the cell wall. In Caulobacter crescentus, however, MreB localizes the protein PilT to the cell poles.

Finally, the authors discuss how RNA is organized in the bacterial cell. These same authors showed that, in E. coli, some mRNAs localized to the same region of the cell as their protein products (a process that was shown to be independent of translation). Specifically, mRNAs coding for membrane proteins accumulated around the cell’s circumference, those coding for cytoplasmic proteins assembled in a helical pattern, and mRNAs for polar proteins assembled at (you guessed it), the poles.

Many questions remain. For example, how do proteins know to go to the cell pole? How many other proteins does MreB interact with? And finally, how do specific mRNAs know where to localize in the cell?

Source: Current Opinion in Microbiology
 
About the Author
  • Kerry received a doctorate in microbiology from the University of Arkansas for Medical Sciences.
You May Also Like
FEB 01, 2021
Cell & Molecular Biology
Dead Cells Can Teach Us About Life's Origins
FEB 01, 2021
Dead Cells Can Teach Us About Life's Origins
When an organism dies, it begins to decay. It's long been assumed that after death, the cells in an organism break down ...
MAR 02, 2021
Chemistry & Physics
Using materials science to fight SARS-CoV-2
MAR 02, 2021
Using materials science to fight SARS-CoV-2
Materials scientists around the world have been hard at work designing and developing materials with antiviral propertie ...
MAR 14, 2021
Microbiology
The Gut Mycobiome - Don't Overlook the Unsung Fungus in Us
MAR 14, 2021
The Gut Mycobiome - Don't Overlook the Unsung Fungus in Us
It was only discovered recently, and the gut microbiome has been shown to be a major player in human health. But bacteri ...
MAR 30, 2021
Neuroscience
Social Support and Compassion Linked to More Diverse Gut Bacteria
MAR 30, 2021
Social Support and Compassion Linked to More Diverse Gut Bacteria
Researchers from the University of California San Diego have found a link between how much social support, compassion, a ...
APR 05, 2021
Microbiology
Salmonella Outbreaks Linked to Bird Feeders, Pet Turtles
APR 05, 2021
Salmonella Outbreaks Linked to Bird Feeders, Pet Turtles
Many types of bacteria often live harmlessly in and on animals and humans, but some bacteria pose a threat. Salmonella b ...
APR 11, 2021
Microbiology
Are Gut Microbes a Solution to Malnutrition?
APR 11, 2021
Are Gut Microbes a Solution to Malnutrition?
The bacteria in our gastrointestinal tract have a big influence on our health, and they serve some important functions i ...
Loading Comments...