Abstract
T cell immunoglobulin and mucin domain 1 and 4 (TIM-1 and -4) proteins serve as phosphatidylserine receptors to engulf apoptotic cells. Here we show that human TIM-1 and TIM-4 proteins are targets of A Disintegrin And Metalloprotease (ADAM)-mediated ectodomain shedding resulting in soluble forms of TIM-1 and TIM-4. We identified ADAM10 and ADAM17 as major sheddases of TIM-1 and TIM-4 as shown by protease-specific inhibitors, the ADAM10 prodomain, siRNA and ADAM10/ADAM17 deficient murine embryonic fibroblasts (MEFs). TIM-1 and TIM-4 lacking the intracellular domain were efficiently cleaved after ionomycin- and PMA-treatment, indicating that the intracellular domain was not necessary for ectodomain shedding. Soluble TIM-1 and -4 were able to bind to phosphatidylserine, suggesting that soluble TIM-1 and -4 might act as negative regulators of cellular TIM-1 and -4. In summary, we describe TIM-1 and TIM-4 as novel targets for ADAM10- and ADAM17-mediated ectodomain shedding.
Keywords:
ADAM; Cell surface receptor; DMEM; Dulbecco's modified Eagle's medium; FBS; Shedding; T cell immunoglobulin and mucin domain protein; fetal bovine serum; mAb; monoclonal antibody.
Copyright © 2013 Elsevier B.V. All rights reserved.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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ADAM Proteins / metabolism*
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ADAM10 Protein
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ADAM17 Protein
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Amino Acid Sequence
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Amino Acids / metabolism
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Amyloid Precursor Protein Secretases / metabolism*
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Animals
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Cell Differentiation / drug effects
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Cell Membrane / drug effects
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Cell Membrane / metabolism
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HEK293 Cells
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Hepatitis A Virus Cellular Receptor 1
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Humans
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Ionomycin / pharmacology
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Membrane Glycoproteins / chemistry
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Membrane Glycoproteins / metabolism*
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Membrane Proteins / chemistry
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Membrane Proteins / metabolism*
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Mice
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Molecular Sequence Data
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Phosphatidylserines / metabolism*
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Protein Binding / drug effects
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Protein Structure, Tertiary
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RNA, Small Interfering / metabolism
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Receptors, Virus / chemistry
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Receptors, Virus / metabolism*
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Sequence Deletion
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Solubility / drug effects
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Tetradecanoylphorbol Acetate / pharmacology
Substances
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Amino Acids
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HAVCR1 protein, human
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Hepatitis A Virus Cellular Receptor 1
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Membrane Glycoproteins
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Membrane Proteins
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Phosphatidylserines
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RNA, Small Interfering
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Receptors, Virus
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TIMD4 protein, human
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Ionomycin
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Amyloid Precursor Protein Secretases
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ADAM Proteins
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ADAM10 Protein
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ADAM10 protein, human
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Adam10 protein, mouse
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ADAM17 Protein
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ADAM17 protein, human
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Adam17 protein, mouse
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Tetradecanoylphorbol Acetate