CD46
Encyclopedia
CD46 complement regulatory protein also known as CD46 (cluster of differentiation
46) and Membrane Cofactor Protein is a protein
which in humans is encoded by the CD46 gene
. CD46 is an inhibitory complement receptor
.
.
The encoded protein has cofactor activity for inactivation of complement components C3b
and C4b by serum factor I, which protects the host cell from damage by complement.
The protein encoded by this gene may be involved in the fusion of the spermatozoa with the oocyte
during fertilization.
.
Established medulloblastoma
(a malignant brain tumor common in childhood) specimens express CD46, and that medulloblastoma specimens removed from patients had a high level of CD46 expression. Therefore a vaccine made of the Edmonston strain of measles virus could treat the medulloblastoma. Such a vaccine has already been tested in a number of trials involving other tumor types which have a high expression of CD46, including one type of adult brain tumor.
with CD9
, CD151
and CD29
.
Cluster of differentiation
The cluster of differentiation is a protocol used for the identification and investigation of cell surface molecules present on white blood cells, providing targets for immunophenotyping of cells...
46) and Membrane Cofactor Protein is a protein
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 CD46 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...
. CD46 is an inhibitory complement receptor
Complement receptor
A complement receptor is a receptor of the complement system, a part of the mediated innate immune system. Complement receptors are responsible for detecting pathogens by mechanisms not mediated by antibodies. Complement activity is not antigen sensitive, but can be triggered by specific antigens...
.
Gene
This gene is found in a cluster on chromosome 1q32 with other genes encoding structural components of the complement system. At least fourteen different transcript variants encoding fourteen different isoforms have been found for this gene.Function
The protein encoded by this gene is a type I membrane protein and is a regulatory part of the complement systemComplement system
The complement system helps or “complements” the ability of antibodies and phagocytic cells to clear pathogens from an organism. It is part of the immune system called the innate immune system that is not adaptable and does not change over the course of an individual's lifetime...
.
The encoded protein has cofactor activity for inactivation of complement components C3b
C3b
C3b is the larger of two elements formed by the cleavage of complement component 3. C3b covalently bonds to microbial cell surfaces within an organism's body. This leads to the production of surface-bound C3 convertase and thus more C3b components. Bound C3b also aids in opsonization of the microbe...
and C4b by serum factor I, which protects the host cell from damage by complement.
The protein encoded by this gene may be involved in the fusion of the spermatozoa with the oocyte
Oocyte
An oocyte, ovocyte, or rarely ocyte, is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum, or egg cell. An oocyte is produced in the ovary during female gametogenesis. The female germ cells produce a primordial germ cell which undergoes a mitotic...
during fertilization.
Clinical Significance
The encoded protein can act as a receptor for the Edmonston strain of measles virus, human herpesvirus-6, and type IV pili of pathogenic NeisseriaNeisseria
The Neisseria is a large genus of commensal bacteria that colonize the mucosal surfaces of many animals. Of the 11 species that colonize humans, only two are pathogens. N. meningitidis and N. gonorrhoeae often cause asymptomatic infections, a commensal-like behavior...
.
Established medulloblastoma
Medulloblastoma
Medulloblastoma is a highly malignant primary brain tumor that originates in the cerebellum or posterior fossa.Previously, medulloblastomas were thought to represent a subset of primitive neuroectodermal tumor of the posterior fossa...
(a malignant brain tumor common in childhood) specimens express CD46, and that medulloblastoma specimens removed from patients had a high level of CD46 expression. Therefore a vaccine made of the Edmonston strain of measles virus could treat the medulloblastoma. Such a vaccine has already been tested in a number of trials involving other tumor types which have a high expression of CD46, including one type of adult brain tumor.
Interactions
CD46 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 CD9
CD9
CD9 antigen is a protein that in humans is encoded by the CD9 gene.-Interactions:CD9 has been shown to interact with TSPAN4, PTGFRN, CD81, CD117, CD46, CD29 and CD49c.-Further reading:...
, CD151
CD151
CD151 molecule , also known as CD151 , is a human gene.-Further reading:...
and CD29
CD29
Integrin beta-1 is a protein that in humans is encoded by the ITGB1 gene. CD29 is an integrin unit associated with very late antigen receptors. It is known to conjoin with alpha-3 subunit to create α3β1 complex that reacts to such molecules as netrin-1 and reelin.Integrins are heterodimeric...
.