Filamin is essential for shedding of the transmembrane serine protease, epithin.
Epithin is a type II transmembrane serine protease that exists in a soluble and membrane-bound form. Shedding is thought to be important in regulating its action, but little is known regarding the intracellular events that trigger such shedding. Here, we show that phorbol myristate acetate (PMA) causes the release of epithin. It also causes accumulation of the protein at the site of cell-cell contacts, and this accumulation is dependent on the formation of cortical actin. In addition, we have identified the actin-binding protein, filamin, as the linker between epithin and the actin cytoskeleton. The interaction of epithin and filamin was enhanced by PMA, and epithin was not released from filamin-deficient M2 cells. We also show that the release of epithin does not require its own activity and is blocked by a metalloprotease inhibitor, GM6001. These results show that filamin has an essential role in shedding by linking epithin to the as yet unidentified metalloprotease-shedding enzyme(s).
Kim
Chungho
C
School of Biological Sciences, Seoul National University, Kwanak-gu, Shilim-dong, Seoul 151-742, Republic of Korea.
Cho
Yongcheol
Y
Kang
Chan-Hee
CH
Kim
Moon Gyo
MG
Lee
HyoSeon
H
Cho
Eun-Gyung
EG
Park
Dongeun
D
D000199:Actins / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D045744:Cell Line, Tumor; D002522:Chlorocebus aethiops; D003285:Contractile Proteins / Q000235:genetics / Q000378:metabolism*; D015638:Cytochalasin D / Q000494:pharmacology; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism; D004151:Dipeptides / Q000494:pharmacology; D064448:Filamins; D006801:Humans; D007365:Intercellular Junctions / Q000187:drug effects / Q000378:metabolism; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D011499:Protein Processing, Post-Translational; D021381:Protein Transport / Q000187:drug effects; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000037:antagonists & inhibitors; D014162:Transfection; D020798:Two-Hybrid System Techniques
D000199:Actins; D003285:Contractile Proteins; D004151:Dipeptides; D064448:Filamins; D008840:Microfilament Proteins; C078131:N-(2(R)-2-(hydroxamidocarbonylmethyl)-4-methylpentanoyl)-L-tryptophan methylamide; D015638:Cytochalasin D; D012697:Serine Endopeptidases; C485596:ST14 protein, human; D008666:Metalloendopeptidases; D013755:Tetradecanoylphorbol Acetate