Apolipoprotein E activates the low-activity form of human phospholipid transfer protein

Biochem Biophys Res Commun. 2005 May 27;331(1):333-40. doi: 10.1016/j.bbrc.2005.03.164.


Phospholipid transfer protein (PLTP) exists in a high-activity (HA-PLTP) and a low-activity form (LA-PLTP) in the circulation. LA-PLTP is associated with apoA-I while the HA-PLTP complex is enriched with apoE. To study the interaction of PLTP with apolipoproteins, we carried out surface plasmon resonance analyses. These demonstrated a concentration-dependent binding of recombinant human PLTP, which represents an active PLTP form, and LA-PLTP to apoE, apoA-I, and apoA-IV within a nanomolar K(D) range. To study whether LA-PLTP can be transformed into an active form, we incubated it in the presence of proteoliposomes containing apoE, apoA-I or apoA-IV. The apoE proteoliposomes induced a concentration-dependent activation of LA-PLTP. ApoA-IV proteoliposomes also activated LA-PLTP in a concentration-dependent manner, whereas apoA-I proteoliposomes had no such effect. These observations suggest that PLTP is capable of interacting with apoE, apoA-I, and apoA-IV, and that these interactions regulate PLTP-activity levels in plasma.

MeSH terms

  • Apolipoprotein A-I / metabolism
  • Apolipoproteins A / metabolism
  • Apolipoproteins E / metabolism*
  • Humans
  • Membrane Proteins / metabolism*
  • Phospholipid Transfer Proteins / metabolism*
  • Proteolipids / chemistry
  • Surface Plasmon Resonance


  • Apolipoprotein A-I
  • Apolipoproteins A
  • Apolipoproteins E
  • Membrane Proteins
  • Phospholipid Transfer Proteins
  • Proteolipids
  • proteoliposomes