biology

Membrane cofactor protein

Membrane cofactor protein is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Membrane cofactor protein rather than just read about it. In short: Membrane cofactor protein (MCP), CD46 complement regulatory protein also known as CD46 (cluster of differentiation 46) is a protein which in humans is encoded by the CD46 gene. CD46 is an inhibitory complement receptor.

Key takeaways

Membrane cofactor protein belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Membrane cofactor protein to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Membrane cofactor protein from memory before moving on to harder problems.

Reference excerpt

Membrane cofactor protein (MCP), CD46 complement regulatory protein also known as CD46 (cluster of differentiation 46) is a protein which in humans is encoded by the CD46 gene. CD46 is an inhibitory complement receptor.

Gene CD46 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 system. The encoded protein has cofactor activity for inactivation (through cleavage) 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.

Clinical significance

Measles infection The encoded protein can act as a receptor for the Edmonston strain of measles virus, human herpesvirus-6 (HHV-6), group B adenoviruses, and type IV pili of pathogenic Neisseria. The extracellular region of CD46 contains four short consensus repeats (SCR) of about 60 amino acids that fold into a compact beta-barrel domain surrounded by flexible loops. As has been demonstrated for CD46 with other ligands, the CD46 protein structure is believed to linearize upon binding HHV-6. While their precise interaction has not yet been determined, the second and third SCR domains have been demonstrated to be required for HHV-6 receptor binding and cellular entry. The heterotetramer gH/gL/gQ1/gQ2 complex of HHV-6 has been identified as a CD46 ligand.

Medulloblastoma 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.

Prostate cancer Recently, CD46 has emerged as a promising target for the treatment of both adenocarcinoma and neuroendocrine types of metastatic castration-resistant prostate cancer (mCRPC). YS5, a human full-length IgG1 with high specificity for CD46, was identified to have high binding affinity for prostate cancer tissue. YS5 has been developed into an antibody-drug conjugate, FOR46, which is currently in a phase I clinical trial (NCT03575819) for the treatment of mCRPC. Since then, a companion molecular imaging agent for CD46-targeted therapy has been developed.

Inflammatory diseases CD46 deficiency contributes to inflammation disorders.

Interactions CD46 has been shown to interact with CD9, CD151 and CD29.

References

External links GeneReviews/NCBI/NIH/UW entry on Atypical Hemolytic-Uremic Syndrome OMIM entries on Atypical Hemolytic-Uremic Syndrome CD46+antigen at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Human CD46 genome location and CD46 gene details page in the UCSC Genome Browser. Overview of all the structural information available in the PDB for UniProt: P15529 (Human Membrane cofactor protein (CD46)) at the PDBe-KB.

Illustrations

Worked examples

Example 1 — a first encounter with Membrane cofactor protein

Start with the simplest possible case. Write down what Membrane cofactor protein claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Membrane cofactor protein before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Membrane cofactor protein ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Membrane cofactor protein

In research: Membrane cofactor protein appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Membrane cofactor protein in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Membrane cofactor protein is common in secondary-school and first-year university syllabi. It links to neighbouring topics Clusters of differentiation, Genes on human chromosome 1, so understanding it makes those chapters shorter.
In everyday life: Look for Membrane cofactor protein outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Membrane cofactor protein in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Membrane cofactor protein means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Membrane cofactor protein out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Membrane cofactor protein in simple terms?

Why does Membrane cofactor protein matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Membrane cofactor protein?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Membrane cofactor protein.