A novel study led by Kristina Jonas (Stockholm University/SciLifeLab Fellow) shows that the molecular chaperone DnaK (Hsp70) is required for growth in the fresh water bacterium Caulobacter crescentus, but that the specific function of DnaK differs depending on the environmental conditions of the cells.

DnaK belongs to a group of proteins called heat shock protein, which have counterparts also in humans. Heat shock proteins are known to play a key role in thermal stress adaption by assisting the folding and refolding of other proteins. In this way, they help to prevent the accumulation of damaged proteins whose folding is disrupted by the increased temperature and that potentially become toxic. 

In various bacteria, including Caulobacter, DnaK is required for cell growth and proliferation at all temperatures. In the current study the authors found that DnaK’s function as a folding catalyst is only required for growth under stress conditions, but not under favorable conditions. Instead, it is DnaK’s function as a regulator of gene expression that determines cell growth under such conditions. It is well-established that in addition to its folding activity DnaK is a negative regulator of the bacterial heat shock sigma factor σ32. The new study demonstrates that this regulatory function of DnaK is a growth requirement and that in the absence of DnaK unleashed σ32 activity inhibits growth and proliferation.

The study shows how Caulobacter and likely many other bacteria appoint the heat-stress responsive protein DnaK to gene regulatory functions to boost cell growth under normal temperature conditions when its role in protein folding and stability is not necessary.

Read the full article in PLOS Genetics

This website uses cookies to improve your experience. We'll assume you're ok with this, but you can opt-out if you wish. Ok!Read More
Privacy & Cookies Policy

Privacy Overview

This website uses cookies to improve your experience while you navigate through the website. Out of these cookies, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. We also use third-party cookies that help us analyze and understand how you use this website. These cookies will be stored in your browser only with your consent. You also have the option to opt-out of these cookies. But opting out of some of these cookies may have an effect on your browsing experience.
Necessary
Always Enabled

Necessary cookies are absolutely essential for the website to function properly. This category only includes cookies that ensures basic functionalities and security features of the website. These cookies do not store any personal information.

Non-necessary

Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. It is mandatory to procure user consent prior to running these cookies on your website.