chemistry

Nectin

Nectin is a chemistry 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 Nectin rather than just read about it. In short: Nectins and Nectin-like molecules (Necl) are families of cellular adhesion molecules involved in Ca2+-independent cellular adhesion. Nectins are ubiquitously expressed and have adhesive roles in a wide range of tissues such as the adherens junction of epithelia or the chemical synapse of the neuronal tissue.

Key takeaways

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

Reference excerpt

Nectins and Nectin-like molecules (Necl) are families of cellular adhesion molecules involved in Ca2+-independent cellular adhesion. Nectins are ubiquitously expressed and have adhesive roles in a wide range of tissues such as the adherens junction of epithelia or the chemical synapse of the neuronal tissue.

Diversity So far four nectins have been identified in humans, namely nectin-1, nectin-2, nectin-3 and nectin-4. These four family members have also been found in most other well studied mammals. Also, five Necls have been identified; these are: Necl-1, Necl-2, Necl-3, Necl-4 and Necl-5.

Structure All nectins and all Necls share the same overall structure defined by three extra cellular immunoglobulin domains, a single transmembrane helix and an intracellular domain. For all nectins the intracellular domain can bind a scaffold protein named afadin (the product of the MLLT4 gene). All nectins and Necls can form homo-cis dimers, meaning a dimer of two alike molecules on the same cell membrane. Following the homo-dimer formation they can trans-interact in an either heterophilic or homophilic manner. The network of the nectin and Necl trans-interactions has been characterized. Recent structural reports reveal the physical and chemical determinants of homophilic interactions mediated by N-terminal IgV domains. In general, heterophilic interactions among nectins have higher affinity than their respective homophilic interactions. Nectins and Necls can also recruit cadherins to enhance binding.

Nomenclature controversy Since the research of nectins has been approached from several angles there is still some controversy about the names of these proteins and the genes encoding them. The idea of grouping these proteins into nectins and Necls originates from Dr. Youhsimi Takai's early studies of the proteins. Nectins and Necls are related in function and protein structure and have been found to interact in a variety of ways, which it is why they are commonly families. However, if one considers the sequence of the genes encoding the proteins, an alternative way of naming the proteins also make sense, as pointed out by Thomas Biederer. Alternative names for nectins and Necls are listed below: nectin-1 : PVRL1 (Poliovirus receptor-related 1), HveC (herpesvirus entry mediator C), CD111 (Cluster of Differentiation 111) nectin-2 : PVRL2 (Poliovirus receptor-related 2), HveB (herpesvirus entry mediator B), CD112 (Cluster of Differentiation 112) nectin-3 : PVRL3 (Poliovirus receptor-related 3), CD113 (Cluster of Differentiation 113) nectin-4 : PVRL4 (Poliovirus receptor-related 4), LNIR; PRR4; EDSS1 necl-1 : CADM3 (Cell adhesion molecule 3), TSLL1 (TSLC1-like 1), SynCAM3 (Synaptic cell adhesion molecule 3), IGSF4B (Immunoglobulin super family member 4B) necl-2 : CADM1 (Cell adhesion molecule 1), TSLC1 (Tumor suppressor in lung cancer 1), SynCAM1 (Synaptic cell adhesion molecule 1), IGSF4 (Immunoglobulin super family member 4), sgIGSF (Spermatogenic immunoglobulin superfamily), RA175 necl-3 : SynCAM2 (Synaptic cell adhesion molecule 2) necl-4 : TSLL2 (TSLC1-like 2), SynCAM4 (Synaptic cell adhesion molecule 1) necl-5 : Tage4, PVR (Poliovirus receptor), CD155

Clinical relevance Nectin-1 and nectin-3 have been shown to be involved in cellular adhesion in some neuronal synapses. Unlike many other cellular adhesion molecules they do not distribute evenly on axonal and dendritic side of the synapse. Instead, Nectin-1 is primarily found on the axonal side and nectin-3 primarily on the dendritic side. Nectin-1 serves as the entry receptor for Herpes Simplex Viruses 1 and 2, binding to the viral envelope glycoprotein gD, and for Pseudorabies Virus. Nectin-4 can be found in the serum of patients with lung cancer. This has led to speculation that this protein might be involved in some developing cancers and might have a pharmaceutical potential. Also, necl-2 is down regulated in a variety of cancers. This is why necl-2 is also known as Tumor suppressor in lung cancer 1 (TSLC1).

As a drug target Nectin-4 : Enfortumab vedotin-ejfv was approved by the FDA in 2019; it is a Nectin-4-directed antibody drug conjugate that has shown clinical activity in metastatic urothelial cancer.

References

Worked examples

Example 1 — a first encounter with Nectin

Start with the simplest possible case. Write down what Nectin claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, 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 Nectin 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 Nectin 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 Nectin

In research: Nectin appears in chemistry 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 Nectin 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: Nectin is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cell adhesion molecules, so understanding it makes those chapters shorter.
In everyday life: Look for Nectin 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 Nectin in 20 minutes

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

Frequently asked questions

What is Nectin in simple terms?

Why does Nectin matter?

Because it connects several chemistry 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 Nectin?

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 Nectin.