Type II cytokine receptors, also commonly known as class II cytokine receptors, are

transmembrane A transmembrane protein (TP) is a type of integral membrane protein that spans the entirety of the cell membrane. Many transmembrane proteins function as gateways to permit the transport of specific substances across the membrane. They frequent ...

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

s that are expressed on the surface of certain cells. They bind and respond to a select group of

cytokine Cytokines are a broad and loose category of small proteins (~5–25 kDa) important in cell signaling. Cytokines are peptides and cannot cross the lipid bilayer of cells to enter the cytoplasm. Cytokines have been shown to be involved in au ...

s including interferon type I, interferon type II,

interferon type III The type III interferon group is a group of anti-viral cytokines, that consists of four IFN-λ (lambda) molecules called IFN-λ1, IFN-λ2, IFN-λ3 (also known as IL29, IL28A and IL28B respectively), and IFN-λ4. They were discovered in 2003. Their ...

. and members of the interleukin-10 family These

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

s are characterized by the lack of a WSXWS motif which differentiates them from type I cytokine receptors.

Structure

Typically type II cytokine receptors are

heterodimers In biochemistry, a protein dimer is a macromolecular complex formed by two protein monomers, or single proteins, which are usually non-covalently bound. Many macromolecules, such as proteins or nucleic acids, form dimers. The word ''dimer'' has ...

or multimers with a high and a low affinity component. These receptors are related predominantly by sequence similarities in their

extracellular This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms. It is intended as introductory material for novices; for more specific and technical definitions ...

portions that are composed of tandem Ig-like domains. The structures for the

domains of the receptors for interferon types, I, II, and III are all known. Type II cytokine receptors are tyrosine-kinase-linked receptors. The intracellular domain of type II cytokine receptors is typically associated with a

tyrosine kinase A tyrosine kinase is an enzyme that can transfer a phosphate group from ATP to the tyrosine residues of specific proteins inside a cell. It functions as an "on" or "off" switch in many cellular functions. Tyrosine kinases belong to a larger cla ...

belonging to the Janus kinase (JAK family). Binding of the receptor typically leads to activation of the canonical JAK/STAT signaling pathway.

Types

Type II cytokine receptors include those that bind

interferon Interferons (IFNs, ) are a group of signaling proteins made and released by host cells in response to the presence of several viruses. In a typical scenario, a virus-infected cell will release interferons causing nearby cells to heighten th ...

s and those that bind members of the

interleukin-10 Interleukin 10 (IL-10), also known as human cytokine synthesis inhibitory factor (CSIF), is an anti- inflammatory cytokine. In humans, interleukin 10 is encoded by the ''IL10'' gene. IL-10 signals through a receptor complex consisting of two IL-10 ...

family (

interleukin-20 Interleukin 20 (IL20) is a protein that is in humans encoded by the ''IL20'' gene which is located in close proximity to the IL-10 gene on the 1q32 chromosome. IL-20 is a part of an IL-20 subfamily which is a part of a larger IL-10 family. ...

interleukin-22 Interleukin-22 (IL-22) is protein that in humans is encoded by the ''IL22'' gene. Structure IL-22 is an α-helical cytokine. IL-22 binds to a heterodimeric cell surface receptor composed of IL-10R2 and IL-22R1 subunits. IL-22R is expressed ...

, and interleukin-28). Expression of specific receptor varieties is highly variable across tissue types with some receptors being ubiquitously expressed and some receptors only expressed in specific tissues.

Interferon receptors

The interferon receptor is a molecule displayed on the surface of cells which interacts with extracellular interferons. Class II cytokine receptors bind type I, type II, and type III interferons. Type I interferons play important roles in both the adaptive and innate immune responses, prevent proliferation of pathogens, and have antiviral activities. Type II interferons help to modulate the immune system’s response to pathogens, and these interferons also respond to pathogens. Type III interferons induce a similar response to type I interferons, but their expression is limited to

epithelial cells Epithelium or epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is a thin, continuous, protective layer of compactly packed cells with a little intercellu ...

. The receptor is coded for by number of different genes, due to the diversity of types of interferons.

Regulation Regulation is the management of complex systems according to a set of rules and trends. In systems theory, these types of rules exist in various fields of biology and society, but the term has slightly different meanings according to context. ...

of cell surface receptor levels plays an important role in the regulation and limiting of interferon signaling. * interferon-alpha/beta receptor * interferon-gamma receptor * Interferon type III receptor

Interleukin receptors

References

2 {{immunology-stub