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Polyphosphate, cyclic AMP, guanosine tetraphosphate, and c-di-GMP reduce in vitro Lon activity

Devon O Osbourne1, Valerie W C Soo1, Igor Konieczny2

  • 1Department of Chemical Engineering; Pennsylvania State University; University Park, PA USA.

Bioengineered
|May 31, 2014
PubMed

Insights

Lon protease, crucial for cellular regulation, is inhibited by phosphate-based molecules like cyclic di-GMP (c-di-GMP) and polyphosphate (polyP). This discovery reveals new ways cellular signals control Lon protease activity.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Cellular Regulation

Background:

  • Lon protease is a conserved enzyme regulating cellular processes by degrading various proteins.
  • Putative cyclic diguanylate (c-di-GMP) binding sites and known interactions with polyphosphate (polyP) suggest Lon may interact with phosphate-based molecules.

Purpose of the Study:

  • To investigate the hypothesis that Lon protease activity is regulated by phosphate-based molecules.
  • To identify specific cellular signals that modulate Lon protease function.

Main Methods:

  • In vitro degradation assays using α-casein as a substrate.
  • Testing the inhibitory effects of polyphosphate (polyP), cyclic adenosine monophosphate (cAMP), cyclic guanosine monophosphate (cGMP), guanosine tetraphosphate (ppGpp), cyclic diguanylate (c-di-GMP), and guanosine monophosphate (GMP).
  • High-performance liquid chromatography (HPLC) to confirm c-di-GMP binding.

Main Results:

  • Polyphosphate (polyP), cyclic adenosine monophosphate (cAMP), guanosine tetraphosphate (ppGpp), and cyclic diguanylate (c-di-GMP) inhibited Lon protease activity in vitro.
  • HPLC analysis confirmed that Lon protease binds to cyclic diguanylate (c-di-GMP).

Conclusions:

  • The activity of Lon protease is regulated by at least four cellular signals: polyP, cAMP, ppGpp, and c-di-GMP.
  • These findings elucidate novel regulatory mechanisms for Lon protease involving phosphate-based signaling molecules.
Keywords:
Lon proteasec-di-GMPcAMPpolyphosphateppGpp

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