IMR Press / FBL / Volume 6 / Issue 1 / DOI: 10.2741/baladron

Frontiers in Bioscience-Landmark (FBL) is published by IMR Press from Volume 26 Issue 5 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on as a courtesy and upon agreement with Frontiers in Bioscience.

Open Access Article
Specific regions of the extracellular domain of dlk, an EGF-like homeotic protein involved in differentiation, participate in intramolecular interactions
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1 Laboratory of Immunobiology, Division of Monoclonal Antibodies, Center for biologics Evaluation and Research, Food and Drug Administration, 1401 Rockville Pike, Rockville, MD 20852, USA
Front. Biosci. (Landmark Ed) 2001, 6(1), 25–32;
Published: 1 November 2001

The level of expression of dlk, an EGF-like protein possessing six EGF-like repeats in its extracellular region, is critical for 3T3-L1 fibroblasts to differentiate into adipocytes in response to IGF1. The mechanism of action of dlk is not well understood, but its localization on the cell membrane suggests that dlk may function as a receptor, as a ligand or as a regulatory protein modulating the binding, the signaling, or the expression of other molecules involved in cell differentiation and growth. In this work, we demonstrate, by using the Yeast Two-Hybrid system, that dlk interacts with itself through specific regions of its extracellular domain. The strongest interactions were observed between specific EGF-like repeats and between a non EFG-like region where unknown proteases act to generate soluble forms of dlk. These observations suggest that the interaction between two membrane dlk molecules belonging to the same or to different cells, or the interaction between soluble and membrane dlk variants, may be important to regulate dlk function.

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