biology

Urokinase receptor

Urokinase receptor 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 Urokinase receptor rather than just read about it. In short: The Urokinase receptor, also known as urokinase plasminogen activator surface receptor (uPAR) or CD87 (Cluster of Differentiation 87), is a protein encoded in humans by the PLAUR gene. It is a multidomain glycoprotein tethered to the cell membrane with a glycosylphosphotidylinositol (GPI) anchor. uPAR was originally identified as a saturable binding site for urokinase (also known as uPA) on the cell surface.

Key takeaways

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

Reference excerpt

The Urokinase receptor, also known as urokinase plasminogen activator surface receptor (uPAR) or CD87 (Cluster of Differentiation 87), is a protein encoded in humans by the PLAUR gene. It is a multidomain glycoprotein tethered to the cell membrane with a glycosylphosphotidylinositol (GPI) anchor. uPAR was originally identified as a saturable binding site for urokinase (also known as uPA) on the cell surface.

Structure uPAR consists of three tandem LU domains, which are protein domains of the three-finger protein family. The structure of uPAR has been solved by X-ray crystallography in complex with a peptide antagonist and with its native ligand, urokinase. All three three-finger domains are necessary for high affinity binding of the primary ligand, urokinase. In addition, uPAR also interacts with several other proteins, including vitronectin, the uPAR associated protein (uPARAP) and the integrin family of membrane proteins. It has been possible to express uPAR recombinantly in CHO-cells and S2 cells from Drosophila melanogaster. 4 out of 5 of the possible glycosylation sites are used in vivo giving the protein a molecular weight of 50–60 kDA.

Function uPAR is a part of the plasminogen activation system, which in the healthy body is involved in tissue reorganization events such as mammary gland involution and wound healing. In order to be able to reorganize tissue, the old tissue must be able to be degraded. An important mechanism in this degradation is the proteolysis cascade initiated by the plasminogen activation system. uPAR binds urokinase and thus restricts plasminogen activation to the immediate vicinity of the cell membrane. When urokinase is bound to the receptor, there is cleavage between the GPI-anchor and the uPAR, releasing a soluble form of the protein known as suPAR.

Clinical significance Soluble urokinase plasminogen activator receptor (suPAR) has been found to be a biomarker of inflammation. Elevated suPAR is seen in chronic obstructive pulmonary disease, asthma, liver failure, heart failure, cardiovascular disease, and rheumatoid arthritis. Smokers have significantly higher suPAR compared to non-smokers. Urokinase receptors have been found to be highly expressed on senescent cells, leading researchers to use chimeric antigen receptor T cells to eliminate senescent cells in mice. The components of the plasminogen activation system have been found to be highly expressed in many malignant tumors, indicating that tumors are able to hijack the system, and use it in metastasis. Thus inhibitors of the various components of the plasminogen activation system have been sought as possible anticancer drugs. uPAR has been involved in various other non-proteolytic processes related to cancer, such as cell migration, cell cycle regulation, and cell adhesion.

Interactions Urokinase receptor has been shown to interact with LRP1.

See also Cancer Cluster of differentiation Metastasis Plasmin suPAR Urokinase

References

Illustrations

Worked examples

Example 1 — a first encounter with Urokinase receptor

Start with the simplest possible case. Write down what Urokinase receptor 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 Urokinase receptor 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 Urokinase receptor 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 Urokinase receptor

In research: Urokinase receptor 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 Urokinase receptor 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: Urokinase receptor is common in secondary-school and first-year university syllabi. It links to neighbouring topics Clusters of differentiation, Genes on human chromosome 19, so understanding it makes those chapters shorter.
In everyday life: Look for Urokinase receptor 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 Urokinase receptor in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Urokinase receptor 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 Urokinase receptor out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Urokinase receptor in simple terms?

Why does Urokinase receptor 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 Urokinase receptor?

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 Urokinase receptor.