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Recently we demonstrated that a 23 kDa form of IGFBP-5, derived from osteoblast-like cells, stimulates osteoblast mitogenesis and enhances IGF-I action. Because osteoblast-derived IGFBP-5 is smaller than recombinant intact IGFBP-5 (23 vs 30 kDa) and has decreased binding affinity for IGF-I, we proposed that the native 23 kDa form of IGFBP-5 was truncated at a carboxy-terminal position. We now show that a recombinant form of carboxy-truncated IGFBP-5 binds IGF-I with reduced affinity and stimulates mitogenesis in mouse osteoblasts. We also show that 125I-truncated IGFBP-5 specifically binds to osteoblast monolayers with low binding affinity, similar to that seen with native 23 kDa IGFBP-5. These data indicate that carboxy-truncated IGFBP-5 stimulates osteoblast mitogenesis and suggest that reduced IGF-binding and cell-surface attachment are local mediators of this response.
D L Andress, and
S M Loop, and
J Zapf, and
M C Kiefer
November 1992,
The Journal of biological chemistry,
D L Andress, and
S M Loop, and
J Zapf, and
M C Kiefer
November 2003,
Pediatric nephrology (Berlin, Germany),
D L Andress, and
S M Loop, and
J Zapf, and
M C Kiefer
May 2008,
Molecular endocrinology (Baltimore, Md.),
D L Andress, and
S M Loop, and
J Zapf, and
M C Kiefer
June 1996,
Endocrinology,
D L Andress, and
S M Loop, and
J Zapf, and
M C Kiefer
April 1991,
Biochemical and biophysical research communications,
D L Andress, and
S M Loop, and
J Zapf, and
M C Kiefer
February 2005,
Bone,
D L Andress, and
S M Loop, and
J Zapf, and
M C Kiefer
December 1997,
The American journal of physiology,
D L Andress, and
S M Loop, and
J Zapf, and
M C Kiefer
April 1998,
The American journal of physiology,
D L Andress, and
S M Loop, and
J Zapf, and
M C Kiefer
September 1993,
Endocrinology,
D L Andress, and
S M Loop, and
J Zapf, and
M C Kiefer
June 1993,
Endocrinology,
