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Susceptibility of mitogen-activated protein kinase kinase family members to proteolysis by anthrax lethal factor

G Vitale1, L Bernardi, G Napolitani

  • 1Centro CNR Biomembrane and Dipartimento di Scienze Biomediche, Università di Padova, Via Trieste 75, 35121 Padova, Italy. gvitale@makek.dstb.uniud.it

The Biochemical Journal
|December 6, 2000
PubMed

Insights

Bacillus anthracis lethal factor (LF) targets multiple mitogen-activated protein kinase kinases (MAPKKs), cleaving them in a specific proline-rich region. This disruption impacts signaling complex assembly and cellular function.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Cellular Signaling

Background:

  • Bacillus anthracis lethal factor (LF) is a zinc-dependent endopeptidase.
  • LF targets specific mitogen-activated protein kinase kinases (MAPKKs), including MEK1, MEK2, and MKK3.
  • The precise targets and cleavage mechanisms of LF require further elucidation.

Purpose of the Study:

  • To investigate the full proteolytic specificity of LF across the entire MAPKK family.
  • To identify the specific peptide bonds hydrolyzed by LF within MAPKKs.
  • To understand the structural and functional implications of LF-mediated cleavage.

Main Methods:

  • Genetic analysis of LF activity.
  • Biochemical assays to determine proteolytic cleavage sites.
  • Sequence alignment to identify consensus motifs at cleavage sites.

Main Results:

  • LF cleaves MKK4, MKK6, and MKK7 in addition to MEK1, MEK2, and MKK3.
  • MEK5 is not cleaved by LF.
  • Cleavage occurs in the N-terminal proline-rich region, disrupting protein-protein interaction sites.

Conclusions:

  • LF exhibits broad specificity towards MAPKKs, targeting a conserved proline-rich region.
  • Cleavage disrupts essential signaling complex assembly, impacting cellular function.
  • Identification of consensus motifs provides insight into LF's enzymatic activity and substrate recognition.

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