title: Role of the ribosome-associated protein PY in the cold-shock response of Escherichia coli.
abstract: Protein Y (PY) is an Escherichia coli cold-shock protein which has been proposed to be responsible for the repression of bulk protein synthesis during cold adaptation. Here, we present in vivo and in vitro data which clarify the role of PY and its mechanism of action. Deletion of yfiA, the gene encoding protein PY, demonstrates that this protein is dispensable for cold adaptation and is not responsible for the shutdown of bulk protein synthesis at the onset of the stress, although it is able to partially inhibit translation. In vitro assays reveal that the extent of PY inhibition changes with different mRNAs and that this inhibition is related to the capacity of PY of binding 30S subunits with a fairly strong association constant, thus stimulating the formation of 70S monomers. Furthermore, our data provide evidence that PY competes with the other ribosomal ligands for the binding to the 30S subunits. Overall these results suggest an alternative model to explain PY function during cold shock and to reconcile the inhibition caused by PY with the active translation observed for some mRNAs during cold shock.
authors: Laboratory of Molecular Biology and Biotechnology, School of Biosciences and Biotechnology, University of Camerino, 62032 Camerino, MC, Italy.
authors: Fabio
authors: F
authors: Di Pietro
authors: Anna
authors: A
authors: Brandi
authors: Nadire
authors: N
authors: Dzeladini
authors: Attilio
authors: A
authors: Fabbretti
authors: Thomas
authors: T
authors: Carzaniga
authors: Lolita
authors: L
authors: Piersimoni
authors: Cynthia L
authors: CL
authors: Pon
authors: Anna Maria
authors: AM
authors: Giuliodori
mesh_terms: D000222:Adaptation, Physiological; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D058639:Cold-Shock Response / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics* / Q000502:physiology; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D008024:Ligands; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012269:Ribosomal Proteins / Q000235:genetics / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D008024:Ligands; D012333:RNA, Messenger; D012269:Ribosomal Proteins; C499682:YfiA protein, bacteria