LDL-receptor-related protein associated protein
Encyclopedia
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
.
family including LRP1
and LRP2
. It is a glycoprotein
that binds to the alpha-2-macroglobulin receptor, as well as to other members of the low density lipoprotein
receptor
family. It acts to inhibit the binding
of all know ligands for these receptors, and may prevent receptor aggregation
and degradation in the endoplasmic reticulum, thereby acting as a molecular chaperone. It may be under the regulatory control of calmodulin, since it is able to bind calmodulin
and be phosphorylated
by calmodulin-dependent kinase
II.
with LRP2
.
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 LRPAP1 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
LRPAP1 is involved with trafficking of certain members of the LDL receptorLDL receptor
The Low-Density Lipoprotein Receptor is a mosaic protein of ~840 amino acids that mediates the endocytosis of cholesterol-rich LDL. It is a cell-surface receptor that recognizes the apoprotein B100 which is embedded in the phospholipid outer layer of LDL particles...
family including LRP1
LRP1
Low density lipoprotein receptor-related protein 1 , also known as alpha-2-macroglobulin receptor , apolipoprotein E receptor or cluster of differentiation 91 , is a protein forming a receptor found in the plasma membrane of cells involved in receptor-mediated endocytosis...
and LRP2
LRP2
Low density lipoprotein-related protein 2 also known as LRP2 or megalin is a protein which in humans is encoded by the LRP2 gene.-Function:...
. It is a glycoprotein
Glycoprotein
Glycoproteins are proteins that contain oligosaccharide chains covalently attached to polypeptide side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. In proteins that have segments extending...
that binds to the alpha-2-macroglobulin receptor, as well as to other members of the low density lipoprotein
Low density lipoprotein
Low-density lipoprotein is one of the five major groups of lipoproteins, which in order of size, largest to smallest, are chylomicrons, VLDL, IDL, LDL, and HDL, that enable transport of cholesterol within the water-based bloodstream...
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...
family. It acts to inhibit the binding
Binding (molecular)
Molecular binding is an attractive interaction between two molecules which results in a stable association in which the molecules are in close proximity to each other...
of all know ligands for these receptors, and may prevent receptor aggregation
Protein aggregation
Protein aggregation is the aggregation of mis-folded proteins, and is thought to be responsible for many degenerative diseases, such as Alzheimer's. It has also been implicated in CAG repeat diseases....
and degradation in the endoplasmic reticulum, thereby acting as a molecular chaperone. It may be under the regulatory control of calmodulin, since it is able to bind calmodulin
Calmodulin
Calmodulin is a calcium-binding protein expressed in all eukaryotic cells...
and be phosphorylated
Phosphorylation
Phosphorylation is the addition of a phosphate group to a protein or other organic molecule. Phosphorylation activates or deactivates many protein enzymes....
by calmodulin-dependent kinase
Kinase
In chemistry and biochemistry, a kinase is a type of enzyme that transfers phosphate groups from high-energy donor molecules, such as ATP, to specific substrates, a process referred to as phosphorylation. Kinases are part of the larger family of phosphotransferases...
II.
Interactions
LDL-receptor-related protein associated protein has been shown to interactProtein-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 LRP2
LRP2
Low density lipoprotein-related protein 2 also known as LRP2 or megalin is a protein which in humans is encoded by the LRP2 gene.-Function:...
.