α-Tocopherol Transfer Protein (α-TTP) is a liver protein responsible for Vitamin E (α-tocopherol) homeostasis in man [1]. The mechanisms by which vitamin E crosses endothelial barriers to enter the brain or the embryo is currently unknown.
We have demonstrated that in specific conditions that also require the presence of α-tocopherol, α-TTP can form nano-spherical particles. We have solved the X-ray structure of such nano-particles and demonstrated their capability of crossing a layer of primary human umbilical vein cells (HUVEC) a common cell culture model for endothelial tissues [2].

This work was carried out in the group of Prof. Achim Stocker.

References:

1. K. Ouahchi, M. Arita, H. Kayden, F. Hentati, M. B. Hamida, R. Sokol, H. Arai, K. Inoue, J.-L. Mandel, M. Koenig;
   "Ataxia with isolated vitamin E deficiency is caused by mutations in the α-tocopherol transfer protein"
   Nature Genetics, 1995, 9(2), 141-145; doi:10.1038/ng0295-141.
2. W. Aeschimann, S. Staats, S. Kammer, N. Olieric, J.-M. Jeckelmann, D. Fotiadis, T. Netscher, G. Rimbach, M. Cascella, A. Stocker;
   "Self-assembled α-Tocopherol Transfer Protein Nanoparticles Promote Vitamin E Delivery Across an Endothelial Barrier"
   Scientific Reports, 2017, 7, 4970/1-13; doi:10.1038/s41598-017-05148-9.