The bone morphogenetic protein receptor, type IA also known as BMPR1A is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
which in humans is encoded by the ''BMPR1A''
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
. BMPR1A has also been designated as CD292 (
cluster of differentiation
The cluster of differentiation (also known as cluster of designation or classification determinant and often abbreviated as CD) is a protocol used for the identification and investigation of cell surface molecules providing targets for immunophe ...
292).
Function
The bone morphogenetic protein (BMP) receptors are a family of transmembrane serine/threonine kinases that include the type I receptors BMPR1A (this protein) and BMPR1B and the type II receptor BMPR2. These receptors are also closely related to the activin receptors, ACVR1 and ACVR2. The ligands of these receptors are members of the
TGF beta
Transforming growth factor beta (TGF-β) is a multifunctional cytokine belonging to the Transforming growth factor beta family, transforming growth factor superfamily that includes three different mammalian isoforms (TGF-β 1 to 3, HUGO Gene Nomen ...
superfamily. TGF-betas and activins transduce their signals through the formation of heterodimeric complexes with 2 different types of serine (threonine) kinase receptors: type I receptors of about 50-55 kD and type II receptors of about 70-80 kD. Type II receptors bind ligands in the absence of type I receptors, but they require their respective type I receptors for signaling, whereas type I receptors require their respective type II receptors for ligand binding.
BMP's repress WNT signaling to maintain stable stem cell populations. BMPR1A null mice died at embryonic day 8.0 without
mesoderm
The mesoderm is the middle layer of the three germ layers that develops during gastrulation in the very early development of the embryo of most animals. The outer layer is the ectoderm, and the inner layer is the endoderm.Langman's Medical ...
specification, demonstrating its vital role in
gastrulation
Gastrulation is the stage in the early embryonic development of most animals, during which the blastula (a single-layered hollow sphere of cells), or in mammals, the blastocyst, is reorganized into a two-layered or three-layered embryo known as ...
. It has been demonstrated in experiments using dominant negative BMPR1A chick embryos that BMPR1A plays a role in
apoptosis
Apoptosis (from ) is a form of programmed cell death that occurs in multicellular organisms and in some eukaryotic, single-celled microorganisms such as yeast. Biochemistry, Biochemical events lead to characteristic cell changes (Morphology (biol ...
and
adipocyte
Adipocytes, also known as lipocytes and fat cells, are the cell (biology), cells that primarily compose adipose tissue, specialized in storing energy as fat. Adipocytes are derived from mesenchymal stem cells which give rise to adipocytes through ...
development. Using constitutively active forms of BMPR1A, it has been shown that BMPR1A plays a role in
cell differentiation
Cellular differentiation is the process in which a stem cell changes from one type to a differentiated one. Usually, the cell changes to a more specialized type. Differentiation happens multiple times during the development of a multicellular ...
. Signals transduced by the BMPR1A receptor are not essential for
osteoblast
Osteoblasts (from the Greek combining forms for " bone", ὀστέο-, ''osteo-'' and βλαστάνω, ''blastanō'' "germinate") are cells with a single nucleus that synthesize bone. However, in the process of bone formation, osteoblasts fu ...
formation or proliferation; however, BMPR1A is necessary for the
extracellular matrix
In biology, the extracellular matrix (ECM), also called intercellular matrix (ICM), is a network consisting of extracellular macromolecules and minerals, such as collagen, enzymes, glycoproteins and hydroxyapatite that provide structural and bio ...
deposition by osteoblasts. In the chick embryo, BMPR1A receptors are found in low levels in limb bud
mesenchyme
Mesenchyme () is a type of loosely organized animal embryonic connective tissue of undifferentiated cells that give rise to most tissues, such as skin, blood, or bone. The interactions between mesenchyme and epithelium help to form nearly ever ...
, a differing location to BMPR1B, supporting the differing roles they play in osteogenesis.
Ligands
*
Agonist
An agonist is a chemical that activates a Receptor (biochemistry), receptor to produce a biological response. Receptors are Cell (biology), cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an R ...
BMP4
Bone morphogenetic protein 4 is a protein that in humans is encoded by ''BMP4'' gene. BMP4 is found on chromosome 14q22-q23.
BMP4 is a member of the bone morphogenetic protein family which is part of the transforming growth factor-beta superfami ...
Antagonists
An antagonist is a character in a story who is presented as the main enemy or rival of the protagonist and is often depicted as a villain.Noggin,
Chordin
Chordin (from Greek χορδή, string, catgut) is a protein with a prominent role in dorsal–ventral patterning during early embryonic development. In humans it is encoded for by the ''CHRD'' gene.
History
Chordin was originally identified ...