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Click-Chemistry Based Fluorometric Assay for Apolipoprotein N-acyltransferase from Enzyme Characterization to High-Throughput Screening
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Apolipoprotein M associates to lipoproteins through its retained signal peptide

Olof Axler1, Josefin Ahnström, Björn Dahlbäck

  • 1Department of Laboratory Medicine, Division of Clinical Chemistry, Lund University, University Hospital, Malmö, Sweden.

FEBS Letters
|February 19, 2008
PubMed

Insights

The signal peptide of apolipoprotein M (apoM) is crucial for its association with lipoproteins like HDL. Without this peptide, apoM remains unassociated with lipids, indicating its essential role in lipid binding.

Area of Science:

  • Lipid Metabolism
  • Molecular Biology
  • Biochemistry

Background:

  • Apolipoprotein M (apoM) is a protein primarily found associated with high-density lipoprotein (HDL) particles in plasma.
  • The precise mechanism by which apoM binds to lipoproteins is not fully understood.
  • The role of the signal peptide in apoM's lipoprotein association requires further investigation.

Purpose of the Study:

  • To determine if the uncleaved signal peptide of apolipoprotein M is essential for its association with lipoproteins.
  • To elucidate the function of the apoM signal peptide in lipid binding.

Main Methods:

  • Expression of wild-type apoM and a Q22A mutant (with a cleavable signal peptide) in HEK293 cells.
  • Analysis of apoM-lipoprotein association using size-exclusion chromatography.

Main Results:

  • Wild-type apoM exhibited an elution profile similar to endogenous HDL-associated apoM.
  • The Q22A mutant apoM eluted as a free, unassociated protein, distinct from HDL particles.
  • These findings demonstrate a significant difference in lipoprotein association between wild-type and mutant apoM.

Conclusions:

  • The signal peptide of apolipoprotein M is necessary for its association with lipoproteins.
  • The uncleaved signal peptide plays a critical role in mediating apoM's binding to lipids.
  • This study highlights the importance of the signal peptide in apoM's function within lipoprotein metabolism.

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