Physiological role of rhomboid proteases in prokaryotes

• Applicant: Privatdozent Dr. Ansgar Poetsch
• Subject Area: Metabolism, Biochemistry and Genetics of Microorganisms
• Term: from 2007 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 46854487

Proteolysis is an important process in eukaryotes and prokaryotes designating the cleavage of cytosolic proteins as well as integral membrane proteins. Thereby either misfolded or misassembled proteins are degraded or proteins are selectively cleaved to become a new functional state which is called “Regulated Intramembrane Proteolysis” (RIP) [1]. While this process takes place inside the membrane, the protein fragments are released into the cytosol or the extracellular space. So far four families of intramembrane proteases are known: presenilins [2], site-2 proteases [3], signal peptide proteases [4] and rhomboid proteases [5]. Rhomboid-proteases are serine proteases that are found in eukaryotes and prokaryotes [6]. These proteases contain 6 to 7 transmembrane helices and a catalytic dyad of histidine and serine which is necessary for proteolysis. The reaction needs no external factors like ATP [7]. Although a lot is known about the function of rhomboid proteases in eukaryotes e.g. the importance of rhomboids for EGFR signal transduction [5], almost nothing is known about the physiological relevance of rhomboid proteases in bacteria. Corynebacterium glutamicum is a gram-positive and non-pathogenic soil bacterium which belongs to the group of actinomycetes. This group of bacteria has a characteristic cell wall, which contains a double layer of long chain mycolic acids at the outer side [8]. For Corynebacterium glutamicum two rhomboid proteases (Cg0049/ NCgl0034 and Cg2767/ NCgl2426) are predicted. The aim of this project is the characterisation of the physiological role of these rhomboid proteases in Corynebacterium glutamicum.

• DFG Programme: Research Grants