Molecular Biology Commons^™

Clpxp Functions In Caulobacter As A Universal And Species-Specific Protease, Robert Vass

Doctoral Dissertations

Proteolysis shapes many aspects of cellular survival, including protein quality control and cellular signaling. Powered proteolysis couples ATP hydrolysis with a degradation force that actively probes and interrogates the protein population. ClpXP, exemplifies a conserved two-part protease system charged with powered proteolysis. This protease exists as a regulatory element (ClpX), and a compartmentalized, self-contained peptidase element (ClpP). In Caulobacter crescentus, ClpXP degradation plays a crucial role maintaining proteins that exhibit proper activity, and also triggers the start of cellular differentiation. Substrate elimination requires shared aspects of the protease from both quality control and precision protein destruction functions. Here, the regulatory …

Adaptors At Work: Regulation Of Bacterial Proteolysis By Adaptor Hierarchies, Kamal Joshi

Doctoral Dissertations

Regulated protein degradation is essential for all life. Bacteria use energy-dependent proteases to regulate protein degradation. Recognition of a substrate is enabled by the inherent specificity of the protease and by the use of adaptor proteins that widen the spectrum of recognized substrates. In Caulobacter crescentus, the timed destruction of many regulators including CtrA by the ClpXP protease drives cell cycle progression. Although, in a test tube, ClpXP can degrade CtrA by itself and does not need any helping factors, additional factors such as CpdR, RcdA and PopA are required in vivo. Understanding how these factors modulate protease …

Control Of Proteolysis During The Caulobacter Cell Cycle, Joanne Lau

Doctoral Dissertations

Intracellular protein destruction is a carefully coordinated and timed regulatory mechanism that cells utilize to modulate growth, adaptation to environmental cues, and survival. In Caulobacter crescentus, a bacterium known for studies of bacterial cell division cycle, the response regulator CpdR couples phosphorylation events with the AAA+ protease ClpXP to provide punctuated degradation of crucial substrates involved in cell cycle regulation. CpdR functions like an adaptor to alter substrate choice by ClpXP, however it remains unclear how CpdR influences its multiple targets. In this thesis, we show that, unlike canonical ClpXP adaptors, CpdR alone does not strongly bind its substrate. …

Novel Adaptor-Dependent Domains Promote Processive Degradation By Clpxp, Keith L. Rood

Masters Theses 1911 - February 2014

Protein degradation by ATP dependent proteases is a universally conserved process. Recognition of substrates by such proteases commonly occurs via direct interaction or with the aid of a regulatory adaptor protein. An example of this regulation is found in Caulobacter crescentus, where key regulatory proteins are proteolysed in a cell-cycle dependent fashion. Substrates include essential transcription factors, structural proteins, and second messenger metabolism components. In this study, we explore sequence and structural requirements for regulated adaptor mediated degradation of PdeA, an important regulator of cyclic-di-GMP levels.

Robust degradation of PdeA is dependent on the response regulator CpdR in vivo …