Parathyroid hormone/parathyroid hormone-related peptide receptor, also known as parathyroid hormone 1 receptor (PTH1R), is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

that in humans is encoded by the ''PTH1R''

gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...

. PTH1R functions as a

receptor Receptor may refer to: * Sensory receptor, in physiology, any structure which, on receiving environmental stimuli, produces an informative nerve impulse *Receptor (biochemistry), in biochemistry, a protein molecule that receives and responds to a ...

for parathyroid hormone ( PTH) and for parathyroid hormone-related protein ( PTHrP), also called parathyroid hormone-like hormone (PTHLH).

Function

This "classical" PTH receptor is expressed in high levels in

bone A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, ...

and

kidney The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blo ...

and regulates

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...

ion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...

homeostasis In biology, homeostasis (British also homoeostasis) (/hɒmɪə(ʊ)ˈsteɪsɪs/) is the state of steady internal, physical, and chemical conditions maintained by living systems. This is the condition of optimal functioning for the organism and ...

through activation of

adenylate cyclase Adenylate cyclase (EC 4.6.1.1, also commonly known as adenyl cyclase and adenylyl cyclase, abbreviated AC) is an enzyme with systematic name ATP diphosphate-lyase (cyclizing; 3′,5′-cyclic-AMP-forming). It catalyzes the following reaction: :A ...

and phospholipase C. In bone, it is expressed on the surface of

osteoblasts 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 function ...

. When the receptor is activated through PTH binding, osteoblasts express RANKL (Receptor Activator of Nuclear Factor kB Ligand), which binds to RANK (Receptor Activator of Nuclear Factor kB) on osteoclasts. This turns on

osteoclasts An osteoclast () is a type of bone cell that breaks down bone tissue. This function is critical in the maintenance, repair, and remodeling of bones of the vertebral skeleton. The osteoclast disassembles and digests the composite of hydrated prote ...

to ultimately increase the resorption rate.

Mechanism

It is a member of the

secretin family Glucagon/gastric inhibitory polypeptide/secretin/vasoactive intestinal peptide hormones are a family of evolutionarily related peptide hormones that regulate activity of G-protein-coupled receptors from the secretin receptor family. A number of ...

G protein-coupled receptor G protein-coupled receptors (GPCRs), also known as seven-(pass)-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptors, and G protein-linked receptors (GPLR), form a large group of evolutionarily-related p ...

s. The activity of this receptor is mediated by G_s

G proteins G proteins, also known as guanine nucleotide-binding proteins, are a family of proteins that act as molecular switches inside cells, and are involved in transmitting signals from a variety of stimuli outside a cell to its interior. Their ac ...

, which activate

adenylyl cyclase Adenylate cyclase (EC 4.6.1.1, also commonly known as adenyl cyclase and adenylyl cyclase, abbreviated AC) is an enzyme with systematic name ATP diphosphate-lyase (cyclizing; 3′,5′-cyclic-AMP-forming). It catalyzes the following reaction: :A ...

. Besides this, they also activate the

phosphatidylinositol Phosphatidylinositol (or Inositol Phospholipid) consists of a family of lipids as illustrated on the right, where red is x, blue is y, and black is z, in the context of independent variation, a class of the phosphatidylglycerides. In such molecul ...

second messenger system.

Pathology

Defects in this receptor are known to be the cause of

Jansen's metaphyseal chondrodysplasia Jansen's metaphyseal chondrodysplasia (JMC) is a disease that results from ligand-independent activation of the type 1 ( PTH1R) of the parathyroid hormone receptor, due to one of three reported mutations (activating mutation). JMC is extremely ...

(JMC) and

chondrodysplasia Blomstrand Chondrodysplasia Blomstrand is a rare disorder caused by mutation of the parathyroid hormone receptor resulting in the absence of a functioning PTHR1. It results in ossification of the endocrine system The endocrine system is a messenger sy ...

type (BOCD) as well as

enchondromatosis Enchondromatosis is a form of osteochondrodysplasia characterized by a proliferation of enchondromas. Ollier disease can be considered a synonym for enchondromatosis. Maffucci syndrome Maffucci syndrome is a very rare disorder in which multiple ...

and primary failure of tooth eruption.

Interactions

Parathyroid hormone 1 receptor has been shown to

interact Advocates for Informed Choice, dba interACT or interACT Advocates for Intersex Youth, is a 501(c)(3) nonprofit organization using innovative strategies to advocate for the legal and human rights of children with intersex traits. The organizati ...

with

Sodium-hydrogen exchange regulatory cofactor 2 Sodium-hydrogen exchange regulatory cofactor NHE-RF2 (NHERF-2) also known as tyrosine kinase activator protein 1 (TKA-1) or SRY-interacting protein 1 (SIP-1) is a protein that in humans is encoded by the ''SLC9A3R2'' (solute carrier family 9 isofo ...

and

Sodium-hydrogen antiporter 3 regulator 1 Sodium-hydrogen antiporter 3 regulator 1 is a regulator of Sodium-hydrogen antiporter 3. It is encoded by the gene ''SLC9A3R1''. It is also known as ERM Binding Protein 50 (EBP50) or Na+/H+ Exchanger Regulatory Factor (NHERF1). It is believed t ...

Model organisms

Model organisms have been used in the study of PTH1R function. A conditional

knockout mouse A knockout mouse, or knock-out mouse, is a genetically modified mouse (''Mus musculus'') in which researchers have inactivated, or " knocked out", an existing gene by replacing it or disrupting it with an artificial piece of DNA. They are importa ...

line called ''Pth1r^{tm1a(EUCOMM)Hmgu}'' was generated at the

Wellcome Trust Sanger Institute The Wellcome Sanger Institute, previously known as The Sanger Centre and Wellcome Trust Sanger Institute, is a non-profit British genomics and genetics research institute, primarily funded by the Wellcome Trust. It is located on the Wellcome G ...

. Male and female animals underwent a standardized

phenotypic screen In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological proper ...

to determine the effects of deletion. Additional screens performed: - In-depth immunological phenotyping

References

External links

* * {{NLM content G protein-coupled receptors