The sclerostin-bone protein interactome.
The secreted glycoprotein, sclerostin alters bone formation. To gain insights into the mechanism of action of sclerostin, we examined the interactions of sclerostin with bone proteins using a sclerostin affinity capture technique. Proteins from decalcified rat bone were captured on a sclerostin-maltose binding protein (MBP) amylose column, or on a MBP amylose column. The columns were extensively washed with low ionic strength buffer, and bound proteins were eluted with buffer containing 1M sodium chloride. Eluted proteins were separated by denaturing sodium-dodecyl sulfate gel electrophoresis and were identified by mass spectrometry. Several previously unidentified full-length sclerostin-interacting proteins such as alkaline phosphatase, carbonic anhydrase, gremlin-1, fetuin A, midkine, annexin A1 and A2, and collagen α1, which have established roles in bone formation or resorption processes, were bound to the sclerostin-MBP amylose resin but not to the MBP amylose resin. Other full-length sclerostin-interacting proteins such as casein kinase II and secreted frizzled related protein 4 that modulate Wnt signaling were identified. Several peptides derived from proteins such as Phex, asporin and follistatin that regulate bone metabolism also bound sclerostin. Sclerostin interacts with multiple proteins that alter bone formation and resorption and is likely to function by altering several biologically relevant pathways in bone.
Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
Hemamalini
H
Devarajan-Ketha
Theodore A
TA
Craig
Benjamin J
BJ
Madden
H
H
Robert Bergen
Rajiv
R
Kumar
D048868:Adaptor Proteins, Signal Transducing; D000469:Alkaline Phosphatase / Q000378:metabolism; D000688:Amylose / Q000737:chemistry; D000818:Animals; D018775:Bone Demineralization Technique; D019485:Bone Morphogenetic Proteins / Q000737:chemistry / Q000378:metabolism*; D001842:Bone and Bones / Q000737:chemistry / Q000378:metabolism*; D047390:Casein Kinase II / Q000737:chemistry / Q000378:metabolism; D002846:Chromatography, Affinity; D005819:Genetic Markers; D006801:Humans; D025941:Protein Interaction Mapping; D020543:Proteome; D011518:Proto-Oncogene Proteins / Q000737:chemistry / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D000094742:Secreted Frizzled-Related Proteins
D048868:Adaptor Proteins, Signal Transducing; D000469:Alkaline Phosphatase; D000688:Amylose; D019485:Bone Morphogenetic Proteins; D047390:Casein Kinase II; D005819:Genetic Markers; D020543:Proteome; D011518:Proto-Oncogene Proteins; C422903:SOST protein, human; C498455:Sfrp4 protein, rat; D000094742:Secreted Frizzled-Related Proteins