biology

Low-density lipoprotein receptor gene family

Low-density lipoprotein receptor gene family 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 Low-density lipoprotein receptor gene family rather than just read about it. In short: The low-density lipoprotein receptor gene family codes for a class of structurally related cell surface receptors that fulfill diverse biological functions in different organs, tissues, and cell types. The role that is most commonly associated with this evolutionarily ancient family is cholesterol homeostasis (maintenance of appropriate concentration of cholesterol).

Key takeaways

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

Reference excerpt

The low-density lipoprotein receptor gene family codes for a class of structurally related cell surface receptors that fulfill diverse biological functions in different organs, tissues, and cell types. The role that is most commonly associated with this evolutionarily ancient family is cholesterol homeostasis (maintenance of appropriate concentration of cholesterol). In humans, excess cholesterol in the blood is captured by low-density lipoprotein (LDL) and removed by the liver via endocytosis of the LDL receptor. Recent evidence indicates that the members of the LDL receptor gene family are active in the cell signalling pathways between specialized cells in many, if not all, multicellular organisms. There are seven members of the LDLR family in mammals, namely:

LDLR VLDL receptor (VLDLR) ApoER2, or LRP8 Low density lipoprotein receptor-related protein 4 also known as multiple epidermal growth factor (EGF) repeat-containing protein (MEGF7) LDLR-related protein 1 LDLR-related protein 1b Megalin.

Human proteins containing this domain Listed below are human proteins containing low-density lipoprotein receptor domains:

Class A C6; C7; 8A; 8B; C9; CD320; CFI; CORIN; DGCR2; HSPG2; LDLR; LDLRAD2; LDLRAD3; LRP1; LRP10; LRP11; LRP12; LRP1B; LRP2; LRP3; LRP4; LRP5; LRP6; LRP8; MAMDC4; MFRP; PRSS7; RXFP1; RXFP2; SORL1; SPINT1; SSPO; ST14; TMPRSS4; TMPRSS6; TMPRSS7; TMPRSS9 (serase-1B); VLDLR;

Class B EGF; LDLR; LRP1; LRP10; LRP1B; LRP2; LRP4; LRP5; LRP5L; LRP6; LRP8; NID1; NID2; SORL1; VLDLR;

See also Soluble low-density lipoprotein receptor-related protein (sLRP) - impaired function is related to Alzheimer's disease.

Structure

The members of the LDLR family are characterized by distinct functional domains present in characteristic numbers. These modules are:

LDL receptor type A (LA) repeats of 40 residues each, displaying a triple-disulfide-bond-stabilized negatively charged surface; certain head-to-tail combinations of these repeats are believed to specify ligand interactions; LDL receptor type B repeats, also known as EGF precursor homology regions, containing EGF-like repeats and YWTD beta propeller domains; a transmembrane domain, and the cytoplasmic region with (a) signal(s) for receptor internalization via coated pits, containing the consensus tetrapeptide Asn-Pro-Xaa-Tyr (NPxY). This cytoplasmic tail controls both endocytosis and signaling by interacting with the phosphotyrosine binding (PTB) domain-containing proteins. In addition to these domains which can be found in all receptors of the gene family, LDL receptor and certain isoforms of ApoER2 and VLDLR contain a short region which can undergo O-linked glycosylation, known as O-linked sugar domain. ApoER2 moreover, can harbour a cleavage site for the protease furin between type A and type B repeats which enables production of a soluble receptor fragment by furin-mediated processing.

References

External links Schematic representation of the seven mammalian LDL receptor (LDLR) family members LDL receptor family members LDL+Receptors at the U.S. National Library of Medicine Medical Subject Headings (MeSH)

Illustrations

Worked examples

Example 1 — a first encounter with Low-density lipoprotein receptor gene family

Start with the simplest possible case. Write down what Low-density lipoprotein receptor gene family 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 Low-density lipoprotein receptor gene family 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 Low-density lipoprotein receptor gene family 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 Low-density lipoprotein receptor gene family

In research: Low-density lipoprotein receptor gene family 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 Low-density lipoprotein receptor gene family 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: Low-density lipoprotein receptor gene family is common in secondary-school and first-year university syllabi. It links to neighbouring topics Low-density lipoprotein receptor gene family, Neurophysiology, Protein families, so understanding it makes those chapters shorter.
In everyday life: Look for Low-density lipoprotein receptor gene family 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 Low-density lipoprotein receptor gene family in 20 minutes

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

Frequently asked questions

What is Low-density lipoprotein receptor gene family in simple terms?

Why does Low-density lipoprotein receptor gene family 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 Low-density lipoprotein receptor gene family?

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 Low-density lipoprotein receptor gene family.