Characterization of three human sec14p-like proteins: α-Tocopherol transport activity and expression pattern in tissues

Jean Marc Zingg, Petra Kempna, Marcel Paris, Elke Reiter, Luis Villacorta, Rita Cipollone, Adelina Munteanu, Clara De Pascale, Stefano Menini, Alexandra Cueff, Michel Arock, Angelo Azzi, Roberta Ricciarelli

Research output: Contribution to journalArticlepeer-review

42 Scopus citations


Three closely related human sec14p-like proteins (hTAP1, 2, and 3, or SEC14L2, 3, and 4, respectively) have been described. These proteins may participate in intracellular lipid transport (phospholipids, squalene, tocopherol analogues and derivatives) or influence regulatory lipid-dependent events. Here, we show that the three recombinant hTAP proteins associate with the Golgi apparatus and mitochondria, and enhance the in vitro transport of radioactively labeled α-tocopherol to mitochondria in the same order of magnitude as the human α-tocopherol transfer protein (α-TTP). hTAP1 and hTAP2 are expressed in several cell lines, whereas the expression level of hTAP3 is low. Expression of hTAP1 is induced in human umbilical cord blood-derived mast cells upon differentiation by interleukin 4. In tissues, the three hTAPs are detectable ubiquitously at low level; pronounced and localized expression is found for hTAP2 and hTAP3 in the perinuclear region in cerebellum, lung, liver and adrenal gland. hTAP3 is well expressed in the epithelial duct cells of several glands, in ovary in endothelial cells of small arteries as well as in granulosa and thecal cells, and in testis in Leydig cells. Thus, the three hTAPs may mediate lipid uptake, secretion, presentation, and sub-cellular localization in a tissue-specific manner, possibly using organelle- and enzyme-specific docking sites.

Original languageEnglish (US)
Pages (from-to)1703-1715
Number of pages13
Issue number11-12
StatePublished - Nov 2008
Externally publishedYes


  • Golgi
  • Mitochondria
  • Phosphatidylinositol kinase
  • Sec14-like proteins
  • Secretion
  • Vitamin E

ASJC Scopus subject areas

  • Biochemistry


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