Ceramidase
Encyclopedia
Ceramidase is an enzyme which cleaves fatty acids from ceramide
, producing sphingosine
(SPH) which in turn is phosphorylated by a sphingosine kinase
to form sphingosine-1-phosphate
(S1P).
, differentiation
, apoptosis
, adhesion
, and migration
. Presently, 7 human ceramidases encoded by 7 distinct genes have been cloned:
Ceramide
Ceramides are a family of lipid molecules. A ceramide is composed of sphingosine and a fatty acid. Ceramides are found in high concentrations within the cell membrane of cells. They are one of the component lipids that make up sphingomyelin, one of the major lipids in the lipid bilayer...
, producing sphingosine
Sphingosine
Sphingosine is an 18-carbon amino alcohol with an unsaturated hydrocarbon chain, which forms a primary part of sphingolipids, a class of cell membrane lipids that include sphingomyelin, an important phospholipid.-Functions:...
(SPH) which in turn is phosphorylated by a sphingosine kinase
Sphingosine kinase
Sphingosine kinase is a conserved lipid kinase that catalyzes formation Sphingosine-1-phosphate from the precursor sphingolipid sphingosine. Sphingolipid metabolites, such as ceramide, sphingosine and sphingosine-1-phosphate, are lipid second messengers involved in diverse cellular processes. ...
to form sphingosine-1-phosphate
Sphingosine-1-phosphate
Sphingosine-1-phosphate is a signaling sphingolipid. It is also referred to as a bioactive lipid mediator. Sphingolipids at large form a class of lipids characterized by a particular aliphatic aminoalcohol, which is sphingosine.-Production:...
(S1P).
Function
Ceramide, SPH, and S1P are bioactive lipids that mediate cell proliferationCell growth
The term cell growth is used in the contexts of cell development and cell division . When used in the context of cell division, it refers to growth of cell populations, where one cell grows and divides to produce two "daughter cells"...
, differentiation
Cellular differentiation
In developmental biology, cellular differentiation is the process by which a less specialized cell becomes a more specialized cell type. Differentiation occurs numerous times during the development of a multicellular organism as the organism changes from a simple zygote to a complex system of...
, apoptosis
Apoptosis
Apoptosis is the process of programmed cell death that may occur in multicellular organisms. Biochemical events lead to characteristic cell changes and death. These changes include blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation...
, adhesion
Cell adhesion
Cellular adhesion is the binding of a cell to a surface, extracellular matrix or another cell using cell adhesion molecules such as selectins, integrins, and cadherins. Correct cellular adhesion is essential in maintaining multicellular structure...
, and migration
Cell migration
Cell migration is a central process in the development and maintenance of multicellular organisms. Tissue formation during embryonic development, wound healing and immune responses all require the orchestrated movement of cells in particular directions to specific locations...
. Presently, 7 human ceramidases encoded by 7 distinct genes have been cloned:
- acid ceramidase (ASAH1ASAH1Acid ceramidase is an enzyme that in humans is encoded by the ASAH1 gene.-Further reading:...
) – cell survival - neutral ceramidase (ASAH2ASAH2Neutral ceramidase is an enzyme that in humans is encoded by the ASAH2 gene.-Further reading:...
, ASAH2BASAH2BNeutral ceramidase B also known as non-lysosomal ceramidase B or N-acylsphingosine amidohydrolase 2B or ASAH2B is a ceramidase enzyme which in humans is encoded by the ASAH2B gene.-Clinical significance:...
, ASAH2CASAH2CNeutral ceramidase C also known as N-acylsphingosine amidohydrolase 2C or non-lysosomal ceramidase C or ASAH2C is a ceramidase enzyme which in humans is encoded by the ASAH2C gene.-Further reading:...
) – protective against inflammatory cytokines - alkaline ceramidase 1 (ACER1ACER1Alkaline ceramidase 1 also known as ACER1 is a ceramidase enzyme which in humans is encoded by the ACER1 gene.- Function :ACER1 mediates cellular differentiation by controlling the generation of sphingosine and sphingosine-1-phosphate ....
) – mediating cell differentiation by controlling the generation of SPH and S1P - alkaline ceramidase 2 (ACER2ACER2Alkaline ceramidase 2 also known as ACER2 is a ceramidase enzyme which in humans is encoded by the ACER2 gene.- Function :The ACER2/sphingosine pathway plays an important role in regulating integrin β1 subunit maturation and cell adhesion mediated by β1 integrins....
) – important for cell proliferation and survival - alkaline ceramidase 3 (ACER3ACER3Alkaline ceramidase 3 also known as ACER3 is a ceramidase enzyme which in humans is encoded by the ACER3 gene....
)