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DIP2 disco‐interacting protein 2 homolog A ( Drosophila ) is a candidate receptor for follistatin‐related protein/follistatin‐like 1 – analysis of their binding with TGF‐β superfamily proteins
Author(s) -
Tanaka Masao,
Murakami Kosaku,
Ozaki Shoichi,
Imura Yoshitaka,
Tong XiaoPeng,
Watanabe Takuo,
Sawaki Toshioki,
Kawanami Takafumi,
Kawabata Daisuke,
Fujii Takao,
Usui Takashi,
Masaki Yasufumi,
Fukushima Toshihiro,
Jin ZheXiong,
Umehara Hisanori,
Mimori Tsuneyo
Publication year - 2010
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2010.07816.x
Subject(s) - follistatin , microbiology and biotechnology , receptor , gene knockdown , chemistry , wnt signaling pathway , bone morphogenetic protein , signal transduction , biology , gene , biochemistry
Follistatin‐related protein (FRP)/follistatin‐like 1 (FSTL1) is a member of the follistatin protein family, all of which share a characteristic structure unit found in follistatin, called the FS domain. Developmental studies have suggested that FRP regulates organ tissue formation in embryos. Immunological studies showed that FRP modifies joint inflammation in arthritic disease, and modulates allograft tolerance. However, the principle physiological function of FRP is currently unknown. To address this issue, we cloned four FRP‐associated proteins using a two‐hybrid cloning method: disco‐interacting protein 2 homolog A from Drosophila (DIP2A), CD14, glypican 1 and titin. Only DIP2A was expected to be a membrane receptor protein with intracellular regions. Over‐expression of FLAG epitope‐tagged DIP2A augmented the suppressive effect of FRP on FBJ murine osteosarcoma viral oncogene homolog (FOS) expression, and the Fab fragment of IgG to FLAG blocked this effect. Knockdown of Dip2a leaded to Fos gene up‐regulation, and this was not affected by exogenous FRP. These in vitro experiments confirmed that DIP2A could be a cell‐surface receptor protein and mediate a FOS down‐regulation signal of FRP. Moreover, molecular interaction analyses using Biacore demonstrated that FRP bound to DIP2A and CD14, and also with proteins of the TGF‐β superfamily, i.e. activin, TGF‐β, bone morphogenetic protein 2/4 (BMP‐2/4), their receptors and follistatin. FRP binding to DIP2A was blocked by CD14, follistatin, activin and BMP‐2. FRP blocked the ligand–receptor binding of activin and BMP‐2, but integrated itself with that of BMP‐4. This multi‐specific binding may reflect the broad physiological activity of FRP. Structured digital abstract• A list of the large number of protein‐protein interactions described in this article is available via the MINT article ID MINT‐7990613