The lysophospholipid receptor (LPL-R) group are members of the

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 ...

family of

integral membrane protein An integral, or intrinsic, membrane protein (IMP) is a type of membrane protein that is permanently attached to the biological membrane. All transmembrane proteins can be classified as IMPs, but not all IMPs are transmembrane proteins. IMPs comp ...

s that are important for

lipid signaling Lipid signaling, broadly defined, refers to any biological cell signaling event involving a lipid messenger that binds a protein target, such as a receptor (biochemistry), receptor, kinase or phosphatase, which in turn mediate the effects of these ...

. In humans, there are eleven LPL

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

, each encoded by a separate gene. These LPL receptor genes are also sometimes referred to as "Edg" (an acronym for endothelial differentiation gene).

Ligands

The ligands for LPL-R group are the lysophospholipid extracellular

signaling molecules In biology, cell signaling (cell signalling in British English) is the process by which a cell interacts with itself, other cells, and the environment. Cell signaling is a fundamental property of all cellular life in both prokaryotes and eukary ...

lysophosphatidic acid A lysophosphatidic acid (LPA) is a phospholipid derivative that can act as a signaling molecule. Function LPA acts as a potent mitogen due to its activation of three high-affinity G-protein-coupled receptors called LPAR1, LPAR2, and LPAR3 (a ...

(LPA) and

sphingosine 1-phosphate Sphingosine-1-phosphate (S1P) is a signaling sphingolipid, also known as lysosphingolipid. It is also referred to as a bioactive lipid mediator. Sphingolipids at large form a class of lipids characterized by a particular aliphatic aminoalcohol ...

(S1P).

Origin of name

The term ''lysophospholipid'' (LPL) refers to any

phospholipid Phospholipids are a class of lipids whose molecule has a hydrophilic "head" containing a phosphate group and two hydrophobic "tails" derived from fatty acids, joined by an alcohol residue (usually a glycerol molecule). Marine phospholipids typ ...

that is missing one of its two O- acyl chains. Thus, LPLs have a free alcohol in either the sn-1 or the sn-2 position. The prefix 'lyso-' comes from the fact that lysophospholipids were originally found to be hemolytic, however it is now used to refer generally to phospholipids missing an acyl chain. LPLs are usually the result of

phospholipase A Phospholipase A can refer to: * Phospholipase A1 * Phospholipase A2 * Outer membrane phospholipase A1 An enzyme that displays both phospholipase A1 and phospholipase A2 activities is called a Phospholipase B (see main article on phospholipase ...

-type enzymatic activity on regular phospholipids such as

phosphatidylcholine Phosphatidylcholines (PC) are a class of phospholipids that incorporate choline as a headgroup. They are a major component of biological membranes and can easily be obtained from a variety of readily available sources, such as egg yolk or soyb ...

phosphatidic acid Phosphatidic acids are anionic phospholipids important to cell signaling and direct activation of lipid-gated ion channels. Hydrolysis of phosphatidic acid gives rise to one molecule each of glycerol and phosphoric acid and two molecules of fatty a ...

, although they can also be generated by the acylation of glycerophospholipids or the phosphorylation of monoacylglycerols. Some LPLs serve important signaling functions such as

Function

LPL receptor ligands bind to and activate their

cognate In historical linguistics, cognates or lexical cognates are sets of words that have been inherited in direct descent from an etymological ancestor in a common parent language. Because language change can have radical effects on both the s ...

receptors located in the cell membrane. Depending on which ligand, receptor, and cell type is involved, the activated receptor can have a range of effects on the cell. These include primary effects of inhibition of

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 ...

and release of

calcium Calcium is a chemical element; it has 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 to it ...

from the

endoplasmic reticulum The endoplasmic reticulum (ER) is a part of a transportation system of the eukaryote, eukaryotic cell, and has many other important functions such as protein folding. The word endoplasmic means "within the cytoplasm", and reticulum is Latin for ...

, as well as secondary effects of preventing

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 increasing

cell proliferation Cell proliferation is the process by which ''a cell grows and divides to produce two daughter cells''. Cell proliferation leads to an exponential increase in cell number and is therefore a rapid mechanism of tissue growth. Cell proliferation ...

Ligands

Origin of name

Function

Group members

See also

References

External links