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Modeling and analysis of molecularinteraction between Smurf1‐WW2 domain and various isoforms of LIM mineralization protein
Author(s) -
Sangadala Sreedhara,
Boden Scott D.,
Metpally Raghu Prasad Rao,
Reddy Boojala Vijay B.
Publication year - 2007
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.21429
Subject(s) - gene isoform , ubiquitin , protein–protein interaction , smad , chemistry , docking (animal) , microbiology and biotechnology , plasma protein binding , homology modeling , biochemistry , biology , signal transduction , enzyme , gene , medicine , nursing
LIM Mineralization Protein‐1 (LMP‐1) has been cloned and shown to be osteoinductive. Our efforts to understand the mode of action of LMP‐1 led to the determination that LMP‐1 interacts with Smad Ubiquitin Regulatory Factor‐1 (Smurf1). Smurf1 targets osteogenic Smads, Smad1/5, for ubiquitin‐mediated proteasomal degradation. Smurf1 interaction with LMP‐1 or Smads is based on the presence of unique WW‐domain interacting motif in these target molecules. By performing site‐directed mutagenesis and binding studies in vitro on purified recombinant proteins, we identified a specific motif within the osteogenic region of several LMP isoforms that is necessary for Smurf1 interaction. Similarly, we have identified that the WW2 domain of Smurf1 is necessary for target protein interaction. Here, we present a homology‐based modeling of the Smurf1 WW2 domain and its interacting motif of LMP‐1. We performed computational docking of the interacting domains in Smurf1 and LMPs to identify the key amino acid residues involved in their binding regions. In support of the computational predictions, we also present biochemical evidence supporting the hypothesis that the physical interaction of Smurf1 and osteoinductive forms of LMP may prevent Smurf1 from targeting osteogenic Smads by ubiquitin‐mediated proteasomal degradation. Proteins 2007. © 2007 Wiley‐Liss, Inc.