From the Gla domain to a novel small-molecule detector of apoptosis

Cell Res. 2009 May;19(5):625-37. doi: 10.1038/cr.2009.17.


Apoptosis plays a pivotal role in the etiology or pathogenesis of numerous medical disorders, and thus, targeting of apoptotic cells may substantially advance patient care. In our quest for novel low-molecular-weight probes for apoptosis, we focused on the uncommon amino acid gamma-carboxyglutamic acid (Gla), which plays a vital role in the binding of clotting factors to negatively charged phospholipid surfaces. Based on the alkyl-malonic acid motif of Gla, we have developed and now present ML-10 (2-(5-fluoro-pentyl)-2-methyl-malonic acid, MW=206 Da), the prototypical member of a novel family of small-molecule detectors of apoptosis. ML-10 was found to perform selective uptake and accumulation in apoptotic cells, while being excluded from either viable or necrotic cells. ML-10 uptake correlates with the apoptotic hallmarks of caspase activation, Annexin-V binding and disruption of mitochondrial membrane potential. The malonate moiety was found to be crucial for ML-10 function in apoptosis detection. ML-10 responds to a unique complex of features of the cell in early apoptosis, comprising irreversible loss of membrane potential, permanent acidification of cell membrane and cytoplasm, and preservation of membrane integrity. ML-10 is therefore the most compact apoptosis probe known to date. Due to its fluorine atom, ML-10 is amenable to radio-labeling with the (18)F isotope, towards its potential future use for clinical positron emission tomography imaging of apoptosis.

MeSH terms

  • 1-Carboxyglutamic Acid / chemistry*
  • Annexin A5 / metabolism
  • Apoptosis*
  • Cell Line
  • Drug Design
  • Fluorescent Dyes / analysis
  • Fluorescent Dyes / chemistry*
  • HeLa Cells
  • Humans
  • Hydrogen-Ion Concentration
  • Jurkat Cells
  • Membrane Potentials
  • Methylmalonic Acid / analogs & derivatives*
  • Methylmalonic Acid / analysis
  • Methylmalonic Acid / chemistry
  • Positron-Emission Tomography
  • Time Factors


  • 5-fluoropentyl-2-methylmalonic acid
  • Annexin A5
  • Fluorescent Dyes
  • 1-Carboxyglutamic Acid
  • Methylmalonic Acid