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J Biol Chem. 2015 Jul 10;290(28):17041-54. doi: 10.1074/jbc.M114.610204. Epub 2015 Apr 29.

Inside-out Regulation of Ectodomain Cleavage of Cluster-of-Differentiation-44 (CD44) and of Neuregulin-1 Requires Substrate Dimerization.

Author information

1
From the Leibniz Institute for Age Research, Fritz Lipmann Institute, 07745 Jena, Germany and.
2
From the Leibniz Institute for Age Research, Fritz Lipmann Institute, 07745 Jena, Germany and the Harvard Institutes of Medicine, Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusett 02115.
3
the Harvard Institutes of Medicine, Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusett 02115.
4
From the Leibniz Institute for Age Research, Fritz Lipmann Institute, 07745 Jena, Germany and herrlich@fli-leibniz.de.

Abstract

Ectodomain shedding of transmembrane precursor proteins generates numerous life-essential molecules, such as epidermal growth factor receptor ligands. This cleavage not only releases the regulatory growth factor, but it is also the required first step for the subsequent processing by γ-secretase and the release of gene regulatory intracellular fragments. Signaling within the cell modifies the cytoplasmic tails of substrates, a step important in starting the specific and regulated cleavage of a large number of studied substrates. Ectodomain cleavage occurs, however, on the outside of the plasma membrane and is carried out by membrane-bound metalloproteases. How the intracellular domain modification communicates with the ectodomain of the substrate to allow for cleavage to occur is unknown. Here, we show that homodimerization of a cluster-of-differentiation-44 or of pro-neuregulin-1 monomers represents an essential pre-condition for their regulated ectodomain cleavage. Both substrates are associated with their respective metalloproteases under both basal or cleavage-stimulated conditions. These interactions only turn productive by specific intracellular signal-induced intracellular domain modifications of the substrates, which in turn regulate metalloprotease access to the substrates' ectodomain and cleavage. We propose that substrate intracellular domain modification induces a relative rotation or other positional change of the dimerization partners that allow metalloprotease cleavage in the extracellular space. Our findings fill an important gap in understanding substrate-specific inside-out signal transfer along cleaved transmembrane proteins and suggest that substrate dimerization (homo- or possibly heterodimerization) might represent a general principle in ectodomain shedding.

KEYWORDS:

ADAM; ADAM10; ADAM17; actin; adhesion molecule; angiotensin; ezrin; metalloprotease; neuregulin

PMID:
25925953
PMCID:
PMC4498042
DOI:
10.1074/jbc.M114.610204
[Indexed for MEDLINE]
Free PMC Article

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