Use of a phage display technique to identify potential osteoblast binding sites within osteoclast lacunae.
There is a temporal coupling between the processes of bone resorption and bone formation in normal skeletal remodeling. That is, osteoblastic activity usually follows episodes of osteoclastic activity. However, what has not been universally appreciated is that there also is a spatial coupling between these processes. Bone formation only occurs in the immediate vicinity of the resorptive event. In this study, we describe a phage display technique that has been used to identify the mechanisms by which osteoblasts recognize components of the prior resorbed lacunar surface. Using a type V tartrate-resistant acid phosphatase (TRAP) as the bait and a random peptide M13 phage display library as the probe, we have identified specific sequences that show a very high affinity for TRAP. One of these peptides, designated clone 5, has a subnanomolar Kd for TRAP, interacts with TRAP in a Far-Western assay, binds exclusively to TRAP within osteoclast lacunae, is present in osteoblasts, and can effectively block osteoblast binding to resorption surfaces. The clone 5 peptide shows a high homology to glypican 4 (GPC4), a proteoglycan attachment receptor found in a number of cell types.
Sheu
Tzong-Jen
TJ
Department of Orthopedics, University of Rochester School of Medicine and Dentistry, New York 14642, USA.
Schwarz
Edward M
EM
O'Keefe
Regis J
RJ
Rosier
Randy N
RN
Puzas
J Edward
JE
D000135:Acid Phosphatase / Q000235:genetics / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D016723:Bone Remodeling / Q000502:physiology; D001862:Bone Resorption / Q000473:pathology / Q000503:physiopathology; D002417:Cattle; D004247:DNA / Q000235:genetics; D019812:Heparan Sulfate Proteoglycans / Q000235:genetics / Q000502:physiology; D066298:In Vitro Techniques; D007527:Isoenzymes / Q000235:genetics / Q000502:physiology; D010006:Osteoblasts / Q000166:cytology / Q000502:physiology*; D010010:Osteoclasts / Q000166:cytology / Q000502:physiology*; D010012:Osteogenesis / Q000502:physiology; D019151:Peptide Library; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D000071681:Tartrate-Resistant Acid Phosphatase
D019812:Heparan Sulfate Proteoglycans; D007527:Isoenzymes; D019151:Peptide Library; D004247:DNA; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase