Versican is a large extracellular matrix
proteoglycan
Proteoglycans are proteins that are heavily glycosylated. The basic proteoglycan unit consists of a "core protein" with one or more covalently attached glycosaminoglycan (GAG) chain(s). The point of attachment is a serine (Ser) residue to whic ...
that is present in a variety of human tissues. It is encoded by the ''VCAN''
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 ...
.
Versican is a large
chondroitin sulfate proteoglycan
Chondroitin sulfate proteoglycans (CSPGs) are proteoglycans consisting of a protein core and a chondroitin sulfate side chain. They are known to be structural components of a variety of human tissues, including cartilage, and also play key roles ...
with an apparent molecular mass of more than 1000kDa. In 1989, Zimmermann and Ruoslahti cloned and sequenced the core protein of fibroblast chondroitin sulfate proteoglycan.
They designated it versican in recognition of its versatile modular structure.
Versican belongs to the
lectican protein family, with
aggrecan
Aggrecan (ACAN), also known as cartilage-specific proteoglycan core protein (CSPCP) or chondroitin sulfate proteoglycan 1, is a protein that in humans is encoded by the ''ACAN'' gene. This gene is a member of the lectican (chondroitin sulfate pr ...
(abundant in
cartilage
Cartilage is a resilient and smooth type of connective tissue. In tetrapods, it covers and protects the ends of long bones at the joints as articular cartilage, and is a structural component of many body parts including the rib cage, the neck ...
),
brevican
Brevican core protein is a protein that in humans is encoded by the ''BCAN'' gene. Brevican is a member of the lectican protein family.
Brevican is localised to the surface of neurons in the brain. In melanocytic cells, BCAN gene expression ...
and
neurocan
Neurocan core protein is a protein that in humans is encoded by the ''NCAN'' gene.
Neurocan is a member of the lectican / chondroitin sulfate proteoglycan protein families and consists of neurocan core protein and chondroitin sulfate. It is thou ...
(nervous system proteoglycans) as other members. Versican is also known as chondroitin sulfate proteoglycan core protein 2 or chondroitin sulfate proteoglycan 2 (CSPG2), and PG-M.
Structure
These proteoglycans share a
homologous globular
N-terminal
The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. Within a peptide, the ami ...
,
C-terminal
The C-terminus (also known as the carboxyl-terminus, carboxy-terminus, C-terminal tail, C-terminal end, or COOH-terminus) is the end of an amino acid chain (protein or polypeptide), terminated by a free carboxyl group (-COOH). When the protein is ...
, and
glycosaminoglycan
Glycosaminoglycans (GAGs) or mucopolysaccharides are long, linear polysaccharides consisting of repeating disaccharide units (i.e. two-sugar units). The repeating two-sugar unit consists of a uronic sugar and an amino sugar, except in the case ...
(GAG) binding regions.
The N-terminal (G1) globular domain consists of
Ig-like loop and two link modules, and has
Hyaluronan
Hyaluronic acid (; abbreviated HA; conjugate base hyaluronate), also called hyaluronan, is an anionic, nonsulfated glycosaminoglycan distributed widely throughout connective, epithelial, and neural tissues. It is unique among glycosaminoglyca ...
(HA) binding properties.
Versican occurs in 5 isoforms : V0, V1, V2, V3, V4.
The central domain of versican V0 contains both the GAG-α and GAG-β domains. V1 isoforms has the GAG-β domain, V2 has the GAG-α domain, V3 is void of any GAG attachment domains and V4 has a portion of the GAG-β domain. The GAGs, being composed of repeating disaccharide units, contribute to the negative charge and many other properties of proteoglycans.
The C-terminal (G3) globular domain consists of one or two
Epidermal growth factor
Epidermal growth factor (EGF) is a protein that stimulates cell growth and differentiation by binding to its receptor, EGFR. Human EGF is 6-k Da and has 53 amino acid residues and three intramolecular disulfide bonds.
EGF was originally de ...
(EGF) repeats, a C-type lectin domain and complement regulatory protein (CRP)-like domain. The C-terminal domain binds a variety of ligands in ECM which contribute significantly to the functions of lecticans.
Function
The role of versican in cell adhesion, migration, and
proliferation has been extensively studied. Versican is often considered an anti-adhesion molecule. Considering the large size (>1000 kDa) and hydration capability of versican, it is possible that the interaction of
integrins
Integrins are transmembrane receptors that facilitate cell-cell and cell-extracellular matrix (ECM) adhesion. Upon ligand binding, integrins activate signal transduction pathways that mediate cellular signals such as regulation of the cell cycle, ...
(large family of cell adhesion molecules) with their cell surface receptors is sterically hindered.
Expression of versican is observed in various adult tissues such as blood vessels, skin, and developing heart. Smooth muscle cells of blood vessels, epithelial cells of skin, and the cells of central and peripheral nervous system are a few examples of cell types that express versican physiologically. Versican is involved in development, guiding embryonic cell migration important in the formation of the heart and outlining the path for neural crest cell migration.
N-terminus
The N-terminal of versican has an important role in maintaining the integrity of the
ECM
ECM may refer to:
Economics and commerce
* Engineering change management
* Equity capital markets
* Error correction model, an econometric model
* European Common Market
Mathematics
* Elliptic curve method
* European Congress of Mathemat ...
by interacting with hyaluronan. Its interactions with link protein has also been studied.
Glycosaminoglycan binding region
The central domain of Versican is decorated with glycosaminoglycans. The structural and functional diversity of Versican is increased by variations in GAG sulfation patterns and the type of GAG chains bound to the core protein. There is a single versican gene, however alternative splicing of its mRNA produces 4 distinct versican isoforms that differ in their potential number of GAG chains. All isoforms have homologous N-terminal (HA binding) and C-terminal (lectin-like) domains. The central domain of versican V0 contains both the GAG-α and GAG-β domains. V1 isoforms has the GAG-β domain, V2 has the GAG-α domain, and V3 is void of any GAG attachment domains, and only consists of the N-terminal and C-terminal globular domains. It is known that the isoforms are differentially expressed in different tissue types. The biological significance of alternative splicing is yet to be determined.
Because of their negatively charged sulfates or carboxyl groups, chondroitin sulfate chains are attracted to various positively charged molecules such as certain growth factors, cytokines, and chemokines. This interaction in the extracellular matrix or on the cell surface is important in the formation of immobilized gradients of these factors, their protection from proteolytic cleavage, and their presentation to specific cell-surface receptors. The binding of versican with leukocyte adhesion molecules L-selectin, P-selectin, and CD44 is also mediated by the interaction of CS chains of versican with the
carbohydrate-binding domain of these molecules. Both CD44 and L-selectin have been implicated in leukocyte trafficking. The ability of versican to bind a large panel of chemokines and the biological consequences of such binding has also been examined. Versican can bind specific chemokines through its CS chains and this interaction down-regulates the chemokines function. Recently, in light of results that V1 and V2 isoforms of versican have opposite effects on cell proliferation, glycosaminoglycan domain GAG-β has been implicated in versican-enhanced cell proliferation and versican-induced reduction of cell apoptosis.
C-terminus
The C-terminal of Versican interacts with a variety of molecules in the matrix. One important family of ligands is the
tenascin
Tenascins are extracellular matrix glycoproteins. They are abundant in the extracellular matrix of developing vertebrate embryos and they reappear around healing wounds and in the stroma of some tumors.
Types
There are four members of the tenasc ...
family. For example, The C-lectin domain of versican interacts with tenascin R through its fibronectin type III (FnIII) repeat 3-5 domain in a calcium dependent manner, ''in vivo''. Different tenascin domains interact with a wide range of cellular receptors, including integrins, cell adhesion molecules and members of the
syndecan and glypican proteoglycan families. Versican’s C-terminal domain interacts with
fibulin-2
Fibulin (FY-beau-lin) (now known as Fibulin-1 FBLN1) is the prototypic member of a multigene family, currently with seven members. Fibulin-1 is a calcium-binding glycoprotein. In vertebrates, fibulin-1 is found in blood and extracellular matri ...
, a protein whose expression is associated with that of versican in the developing heart. The EGF domain of the C-terminal of versican also binds the EGF-receptor molecule ''in vivo''.
Clinical significance
Versican is a key factor in inflammation through interactions with adhesion molecules on the surfaces of inflammatory leukocytes and interactions with chemokines that are involved in recruiting inflammatory cells.
In the adult central nervous system, versican is found in
perineuronal net
Perineuronal nets (PNNs) are specialized extracellular matrix structures responsible for synaptic stabilization in the adult brain. PNNs are found around certain neuron cell bodies and proximal neurites in the central nervous system. PNNs play a c ...
s, where it may stabilize synaptic connections. Versican can also inhibit nervous system regeneration and axonal growth following an injury to the central nervous system.
Cancer and metastasis
Increased versican expression is often observed in tumor growth in tissues such as breast, brain, ovary, gastrointestinal tract, prostate, and
melanoma
Melanoma, also redundantly known as malignant melanoma, is a type of skin cancer that develops from the pigment-producing cells known as melanocytes. Melanomas typically occur in the skin, but may rarely occur in the mouth, intestines, or eye ( ...
,
sarcoma
A sarcoma is a malignant tumor, a type of cancer that arises from transformed cells of mesenchymal ( connective tissue) origin. Connective tissue is a broad term that includes bone, cartilage, fat, vascular, or hematopoietic tissues, and sar ...
, and
peritoneal mesothelioma. A fifth isoform of versican, V4, that is similar to V1 but with a shortened beta-GAG region, is present and upregulated in human
breast
The breast is one of two prominences located on the upper ventral region of a primate's torso. Both females and males develop breasts from the same embryological tissues.
In females, it serves as the mammary gland, which produces and sec ...
cancer.
Versican is required for
Lewis lung carcinoma in mice to metastasize to lung, liver and adrenal glands, acting via
TLR2
Toll-like receptor 2 also known as TLR2 is a protein that in humans is encoded by the ''TLR2'' gene. TLR2 has also been designated as CD282 (cluster of differentiation 282). TLR2 is one of the toll-like receptors and plays a role in the immune sys ...
to activate
myeloid cell
A myelocyte is a young cell of the granulocytic series, occurring normally in bone marrow (can be found in circulating blood when caused by certain diseases).
Structure
When stained with the usual dyes, the cytoplasm is distinctly basophil ...
s and produce
TNF-alpha
Tumor necrosis factor (TNF, cachexin, or cachectin; formerly known as tumor necrosis factor alpha or TNF-α) is an adipokine and a cytokine. TNF is a member of the TNF superfamily, which consists of various transmembrane proteins with a homolog ...
.
Lung disorders
Versican is increased in the changing tissue
extracellular matrix
In biology, the extracellular matrix (ECM), also called intercellular matrix, is a three-dimensional network consisting of extracellular macromolecules and minerals, such as collagen, enzymes, glycoproteins and hydroxyapatite that provide s ...
in inflammatory lung disorders such as
chronic obstructive pulmonary disease
Chronic obstructive pulmonary disease (COPD) is a type of progressive lung disease characterized by long-term respiratory symptoms and airflow limitation. The main symptoms include shortness of breath and a cough, which may or may not produce ...
(COPD),
asthma
Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, co ...
and bronchiolitis obliterans syndrome (BOS).
Cells
Cell most often refers to:
* Cell (biology), the functional basic unit of life
Cell may also refer to:
Locations
* Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery w ...
(
myofibroblasts,
macrophage
Macrophages (abbreviated as M φ, MΦ or MP) ( el, large eaters, from Greek ''μακρός'' (') = large, ''φαγεῖν'' (') = to eat) are a type of white blood cell of the immune system that engulfs and digests pathogens, such as cancer ce ...
s and other inflammatory cells) can migrate more easily through
extracellular matrix
In biology, the extracellular matrix (ECM), also called intercellular matrix, is a three-dimensional network consisting of extracellular macromolecules and minerals, such as collagen, enzymes, glycoproteins and hydroxyapatite that provide s ...
that has a higher versican content.
Skin
Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation.
Other animal coverings, such as the arthropod exoskeleton, have different ...
disorders
Deposits of versican are not present in normal
skin
Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation.
Other animal coverings, such as the arthropod exoskeleton, have different ...
but are found in the
reticular dermis during
keloid
Keloid, also known as keloid disorder and keloidal scar,
is the formation of a type of scar which, depending on its maturity, is composed mainly of either type III (early) or type I (late) collagen. It is a result of an overgrowth of granulation ...
scarring, a condition where
scar
A scar (or scar tissue) is an area of fibrous tissue that replaces normal skin after an injury. Scars result from the biological process of wound repair in the skin, as well as in other organs, and tissues of the body. Thus, scarring is a ...
formation becomes uncontrolled and overgrowth of
skin
Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation.
Other animal coverings, such as the arthropod exoskeleton, have different ...
tissue occurs at the site of the
wound
A wound is a rapid onset of injury that involves lacerated or punctured skin (an ''open'' wound), or a contusion (a ''closed'' wound) from blunt force trauma or compression. In pathology, a ''wound'' is an acute injury that damages the epider ...
.
Interactions
Versican has been shown to
interact
Advocates for Informed Choice, doing business as, 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 trai ...
with hyaluronan and a link protein (hyaluronan and proteoglycan link protein 1;
HAPLN1
Hyaluronan and proteoglycan link protein 1 is a protein that in humans is encoded by the ''HAPLN1'' gene.
Interactions
HAPLN1 has been shown to interact
Advocates for Informed Choice, doing business as, dba interACT or interACT Advocates ...
).
References
Further reading
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External links
GeneReviews/NCBI/NIH/UW entry on VCAN-Related Vitreoretinopathy Includes: Wagner Vitreoretinal Degeneration (Wagner Syndrome), Erosive Vitreoretinopathy (ERVR)*
{{Proteoglycans
Lecticans
C-type lectins
Extracellular matrix proteins