Membrane interactions and lipid binding of casein oligomers and early aggregates

Miri Sokolovski, Tania Sheynis, Sofiya Kolusheva, Raz Jelinek

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

Caseins constitute the main protein components in mammalian milk and have critical functions in calcium transport and prevention of protein aggregation. Fibrillation and aggregation of κ-casein, a phenomenon which has only recently been detected, might be associated with malfunctions of milk secretion and amyloidosis phenomena in the mammary glands. This study employs a newly-designed chromatic biomimetic vesicle assay to investigate the occurrence and the parameters affecting membrane interactions of casein aggregates and the contribution of individual casein members to membrane binding. We show that physiological casein colloids exhibit membrane activity, as well as early globular aggregates of κ-casein, a prominent casein isoform. Furthermore, inhibition of κ-casein fibrillation through complexation with αS-casein and β-casein, respectively, was found to go hand in hand with induction of enhanced membrane binding; these data are important in the context of casein biology since in secreted milk κ-casein is found only in assemblies containing also αS-casein and β-casein. The chromatic experiments, complemented by transmission electron microscopy analysis and fluorescence quenching assays, also revealed significantly higher affinity early spherical aggregates of k-casein to anionic phosphatidylglycerol-lipids, as compared to zwitterionic phospholipids. Overall, this study suggests that lipid interactions play important roles in maintaining the essential physiological functions of caseins in mammalian milk.

Original languageEnglish
Pages (from-to)2341-2349
Number of pages9
JournalBiochimica et Biophysica Acta - Biomembranes
Volume1778
Issue number10
DOIs
StatePublished - 1 Oct 2008

Keywords

  • Amyloidogenic protein
  • Casein
  • Casein fibrils
  • Membrane interaction
  • Polydiacetylene
  • Pre-fibril oligomers

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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