E. coli transports aggregated proteins to the poles by a specific and energy-dependent process.
Aggregation of proteins due to failure of quality control mechanisms is deleterious to both eukaryotes and prokaryotes. We found that in Escherichia coli, protein aggregates are delivered to the pole and form a large polar aggregate (LPA). The formation of LPAs involves two steps: the formation of multiple small aggregates and the delivery of these aggregates to the pole to form an LPA. Formation of randomly distributed aggregates, their delivery to the poles, and LPA formation are all energy-dependent processes. The latter steps require the proton motive force, activities of the DnaK and DnaJ chaperones, and MreB. About 90 min after their formation, the LPAs are dissolved in a process that is dependent upon ClpB, DnaK, and energy. Our results confirm and substantiate the notion that the formation of LPAs allows asymmetric inheritance of the aggregated proteins to a small number of daughter cells, enabling their rapid elimination from most of the bacterial population. Moreover, the results show that the processing of aggregated proteins by the protein quality control system is a multi-step process with distinct spatial and temporal controls.
Rokney
Assaf
A
Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University, Jerusalem, Israel. assaf.rokney@mail.huji.ac.il
Shagan
Merav
M
Kessel
Martin
M
Smith
Yoav
Y
Rosenshine
Ilan
I
Oppenheim
Amos B
AB
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D016764:Cell Polarity; D049071:Endopeptidase Clp; D004734:Energy Metabolism; D004926:Escherichia coli / Q000166:cytology / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D050956:HSP40 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D051082:Homoserine O-Succinyltransferase / Q000235:genetics / Q000378:metabolism; D002479:Inclusion Bodies / Q000378:metabolism*; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D054334:Viral Regulatory and Accessory Proteins / Q000235:genetics / Q000378:metabolism
C494635:DnaJ protein, E coli; D029968:Escherichia coli Proteins; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D054334:Viral Regulatory and Accessory Proteins; C016649:phage repressor proteins; D000255:Adenosine Triphosphate; D051082:Homoserine O-Succinyltransferase; C494973:metA protein, E coli; D049071:Endopeptidase Clp; C063842:dnaK protein, E coli; C069775:ClpB protein, E coli