Non-classical Protein Excretion Is Boosted by PSMα-Induced Cell Leakage

Patrick Ebner, Arif Luqman, Sebastian Reichert, Ksenia Hauf, Peter Popella, Karl Forchhammer, Michael Otto, Friedrich Götz*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

51 Citations (Scopus)


Release of cytoplasmic proteins into the supernatant occurs both in bacteria and eukaryotes. Because the underlying mechanism remains unclear, the excretion of cytoplasmic proteins (ECP) has been referred to as “non-classical protein secretion.” We show that none of the known specific protein transport systems of Gram-positive bacteria are involved in ECP. However, the expression of the cationic and amphipathic α-type phenol-soluble modulins (PSMs), particularly of PSMα2, significantly increase ECP, while PSMβ peptides or δ-toxin have no effect on ECP. Because psm expression is strictly controlled by the accessory gene regulator (agr), ECP is also reduced in agr-negative mutants. PSMα peptides damage the cytoplasmic membrane, as indicated by the release of not only CPs but also lipids, nucleic acids, and ATP. Thus, our results show that in Staphylococcus aureus, PSMα peptides non-specifically boost the translocation of CPs by their membrane-damaging activity.

Original languageEnglish
Pages (from-to)1278-1286
Number of pages9
JournalCell Reports
Issue number6
Publication statusPublished - 8 Aug 2017
Externally publishedYes


  • Staphylococcus aureus
  • aldolase
  • cytoplasmic proteins
  • enolase
  • membrane damage
  • non-classical protein secretion
  • phenol-soluble-modulins


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