Low density lipoprotein-related protein 2 also known as LRP2 or megalin is a protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 which in humans is encoded by the LRP2 gene

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

.

Function

LRP2 is a multiligand binding receptor

Receptor (biochemistry)

In biochemistry, a receptor is a molecule found on the surface of a cell, which receives specific chemical signals from neighbouring cells or the wider environment within an organism...

 found in the plasma membrane of many absorptive epithelial cell

Cell biology

Cell biology is a scientific discipline that studies cells – their physiological properties, their structure, the organelles they contain, interactions with their environment, their life cycle, division and death. This is done both on a microscopic and molecular level...

s. LRP2 is a member of a family of receptors with structural similarities to the low density lipoprotein receptor (LDLR). LRP2 functions to mediate endocytosis

Endocytosis

Endocytosis is a process by which cells absorb molecules by engulfing them. It is used by all cells of the body because most substances important to them are large polar molecules that cannot pass through the hydrophobic plasma or cell membrane...

 of ligands leading to degradation in lysosomes or transcytosis. LRP2 (previously called glycoprotein 330) together with RAP (LRPAP1) forms the Heymann nephritis antigenic complex. LRP2 is expressed in epithelial cells of the thyroid

Thyroid

The thyroid gland or simply, the thyroid , in vertebrate anatomy, is one of the largest endocrine glands. The thyroid gland is found in the neck, below the thyroid cartilage...

 (thyrocytes), where it can serve as a receptor for the protein thyroglobulin

Thyroglobulin

Thyroglobulin is a 660 kDa, dimeric protein produced by and used entirely within the thyroid gland. In earlier literature, Tg was referred to as colloid....

 (Tg).

Clinical significance

Mutations in the LRP2 gene are associated with Donnai-Barrow syndrome

Donnai-Barrow syndrome

Donnai-Barrow syndrome is a genetic disorder. It is associated with LRP2. It is an inherited disorder that affects many parts of the body.-Physical characterisitics:...

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Interactions

LRP2 has been shown to interact

Protein-protein interaction

Protein–protein interactions occur when two or more proteins bind together, often to carry out their biological function. Many of the most important molecular processes in the cell such as DNA replication are carried out by large molecular machines that are built from a large number of protein...

 with LDL-receptor-related protein associated protein

LDL-receptor-related protein associated protein

Low density lipoprotein receptor-related protein associated protein 1 also known as LRPAP1 or RAP is a chaperone protein which in humans is encoded by the LRPAP1 gene.- Function :...

, LDLRAP1

LDLRAP1

Low density lipoprotein receptor adapter protein 1 is a protein that in humans is encoded by the LDLRAP1 gene.-Interactions:LDLRAP1 has been shown to interact with AP2B1 and LRP2.-Further reading:...

, MAPK8IP2

MAPK8IP2

C-jun-amino-terminal kinase-interacting protein 2 is an enzyme that in humans is encoded by the MAPK8IP2 gene.-Interactions:MAPK8IP2 has been shown to interact with MAP3K10, Mitogen-activated protein kinase 9, LRP2, LRP1, MAPK8IP3, MAP3K12, MAPK8IP1, MAP2K7 and MAP3K11.-Further reading:...

, MAGI1

MAGI1

Membrane-associated guanylate kinase, WW and PDZ domain-containing protein 1 is an enzyme that in humans is encoded by the MAGI1 gene.-Interactions:...

, SYNJ2BP

SYNJ2BP

Synaptojanin-2-binding protein is a protein that in humans is encoded by the SYNJ2BP gene.-Interactions:SYNJ2BP has been shown to interact with LRP2, ACVR2B, ACVR2A and LRP1.-Further reading:...

, DLG4

DLG4

PSD-95 also known as SAP-90 is a protein that in humans is encoded by the DLG4 gene....

, NOS1AP

NOS1AP

Nitric oxide synthase 1 adaptor protein also known as carboxyl-terminal PDZ ligand of neuronal nitric oxide synthase protein is a protein that in humans is encoded by the NOS1AP gene....

, DAB2

DAB2

Disabled homolog 2 is a protein that in humans is encoded by the DAB2 gene.-Interactions:DAB2 has been shown to interact with C-src tyrosine kinase, Cdk1, Src, LRP2, DVL3, PIN1, MYO6, DVL2, DAB2IP, Mothers against decapentaplegic homolog 3 and Mothers against decapentaplegic homolog 2.-Further...

, ITGB1BP1

ITGB1BP1

Integrin beta-1-binding protein 1 is a protein that in humans is encoded by the ITGB1BP1 gene.-Interactions:ITGB1BP1 has been shown to interact with KRIT1, LRP2, CD29 and LRP1.-Further reading:...

, MAPK8IP1

MAPK8IP1

C-jun-amino-terminal kinase-interacting protein 1 is an enzyme that in humans is encoded by the MAPK8IP1 gene.-Interactions:MAPK8IP1 has been shown to interact with MAP3K10, DUSP16, Mitogen-activated protein kinase 9, MAPK8, LRP2, LRP1, MAP3K12, MAP2K7, MAPK8IP2 and MAP3K11.-Further reading:...

 and GIPC1

GIPC1

GIPC PDZ domain containing family, member 1 is a protein that in humans is encoded by the GIPC1 gene.-Interactions:GIPC1 has been shown to interact with Beta-1 adrenergic receptor, ITGA5, ITGA6, TPBG, RGS19, TYRP1, GLUT1, Actinin, alpha 1, KIF1B, LRP2, Luteinizing hormone/choriogonadotropin...

.

External links

• GeneReviews/NCBI/NIH/UW entry on Donnai-Barrow Syndrome