biology

Thrombospondin

Thrombospondin 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 Thrombospondin rather than just read about it. In short: Thrombospondins (TSPs) are a family of secreted glycoproteins with antiangiogenic functions. Due to their dynamic role within the extracellular matrix they are considered matricellular proteins.

Key takeaways

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

Reference excerpt

Thrombospondins (TSPs) are a family of secreted glycoproteins with antiangiogenic functions. Due to their dynamic role within the extracellular matrix they are considered matricellular proteins. The first member of the family, thrombospondin 1 (THBS1), was discovered in 1971 by Nancy L. Baenziger.

Types The thrombospondins are a family of multifunctional proteins. The family consists of thrombospondins 1–5 and can be divided into two subgroups: A, which contains TSP-1 and TSP-2, and B, which contains TSP-3, TSP-4 and TSP-5 (also designated cartilage oligomeric protein or COMP). TSP-1 and TSP-2 are homotrimers, consisting of three identical subunits, whereas TSP-3, TSP-4 and TSP-5 are homopentamers. TSP-1 and TSP-2 are produced by immature astrocytes during brain development, which promotes the development of new synapses.

Thrombospondin 1

Thrombospondin 1 (TSP-1) is encoded by THBS1. It was first isolated from platelets that had been stimulated with thrombin, and so was designated 'thrombin-sensitive protein'. Since its first recognition, functions for TSP-1 have been found in multiple biological processes including angiogenesis, apoptosis, activation of TGF-beta and Immune regulation. As such, TSP-1 is designated a multifunctional protein. TSP-1 has multiple receptors, among which CD36, CD47 and integrins are of particular note. TSP-1 is antiangiogenic, inhibiting the proliferation and migration of endothelial cells by interactions with CD36 expressed on their surface of these cells. Inhibitory peptides and fragments of TSP1 bind to CD36, leading to the expression of FAS ligand (FasL), which activates its specific, ubiquitous receptor, Fas. This leads to the activation of caspases and apoptosis of the cell. Since tumors overexpressing TSP-1 typically grow slower, exhibit less angiogenesis, and have fewer metastases, TSP1 is an attractive target for cancer treatment. Because TSP1 is extremely large (~ 120 kDa monomer), not very abundant and exerts multiple actions, its clinical usefulness is questionable. However, small-molecules based on a CD36-binding peptide sequence from TSP1 are being tested. One analog, ABT-510, exhibits potent proapoptotic activity in cultured cells, while clinically it is very well tolerated with therapeutic benefits reported against several malignancies. In 2005, ABT-510 was evaluated in phase II clinical trials for the treatment of several types of cancer.

Human proteins containing this domain ADAMTS1; ADAMTS10; ADAMTS12; ADAMTS13; ADAMTS14; ADAMTS15; ADAMTS16; ADAMTS17; ADAMTS18; ADAMTS19; ADAMTS2; ADAMTS20; ADAMTS3; ADAMTS4; ADAMTS5; ADAMTS6; ADAMTS7; ADAMTS8; ADAMTS9; ADAMTSL1; ADAMTSL2; ADAMTSL3; ADAMTSL4; ADAMTSL5; BAI1; BAI2; BAI3; C6; C7; C8A; C8B; C9; C9orf8; C9orf94; CFP; CILP; CILP2; CTGF; CYR61; HMCN1; LIBC; NOV; PAPLN; RSPO1; RSPO3; SEMA5A; SEMA5B; SPON1; SPON2; SSPO; THBS1; THBS2; THSD1; THSD3; THSD7A; THSD7B; UNC5A; UNC5B; UNC5C; UNC5D; WISP1; WISP2; WISP3;

References

External links Thrombospondins at the U.S. National Library of Medicine Medical Subject Headings (MeSH) THBS1, THBS2, THBS3, THBS4, COMP (also known as "THBS5")

Illustrations

Worked examples

Example 1 — a first encounter with Thrombospondin

Start with the simplest possible case. Write down what Thrombospondin 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 Thrombospondin 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 Thrombospondin 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 Thrombospondin

In research: Thrombospondin 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 Thrombospondin 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: Thrombospondin is common in secondary-school and first-year university syllabi. It links to neighbouring topics Protein domains, Thrombospondins, so understanding it makes those chapters shorter.
In everyday life: Look for Thrombospondin 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 Thrombospondin in 20 minutes

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

Frequently asked questions

What is Thrombospondin in simple terms?

Thrombospondins (TSPs) are a family of secreted glycoproteins with antiangiogenic functions. Due to their dynamic role within the extracellular matrix they are considered matricellular proteins.

Why does Thrombospondin 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 Thrombospondin?

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 Thrombospondin.