Bone Morphogenetic Protein Receptors

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Bone Morphogenetic Protein Receptors
SIGMA-ALDRICH
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Bone Morphogenetic Protein Receptors Bone
morphogenetic protein (BMP) induces ectopic bone
formation, and plays an important role in the
development of the viscera. Ligand binding to its
receptor induces the formation of a complex in
which the Type II BMP receptor phosphorylates and
activates the Type I BMP receptor. The Type I BMP
receptor then propagates the signal by
phosphorylating a family of signal transducers,
the Smad proteins. Currently, eight Smad proteins
have been cloned (Smad 1-7 and Smad 9). Upon
phosphorylation by the BMP Type I receptor, Smad1
can interact with either Smad4 or Smad6. The
Smad1-Smad6 complex is inactive however, the
Smad1-Smad4 complex triggers the expression of
BMP responsive genes. The ratio between Smad4 and
Smad6 in the cell can modulate the strength of
the signal transduced by BMP. References Fuji,
M., et al., Roles of bone morphogenetic protein
type I receptors and Smad proteins in osteoblast
and chondroblast differentiation. Mol. Biol.
Cell., 10, 3801-3813 (1999). Kawabata, M., et
al., Signal transduction by bone morphogenetic
proteins. Cytokine Growth Factor Rev., 9, 49-61
(1998).