biology

Immunoreceptor tyrosine-based activation motif

Immunoreceptor tyrosine-based activation motif 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 Immunoreceptor tyrosine-based activation motif rather than just read about it. In short: An immunoreceptor tyrosine-based activation motif (ITAM) is a conserved sequence of four amino acids that is repeated twice in the cytoplasmic tails of non-catalytic tyrosine-phosphorylated receptors, cell-surface proteins found mainly on immune cells. Its major role is being an integral component for the initiation of a variety of signaling pathway and subsequently the activation of immune cells, although different…

Key takeaways

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

Reference excerpt

An immunoreceptor tyrosine-based activation motif (ITAM) is a conserved sequence of four amino acids that is repeated twice in the cytoplasmic tails of non-catalytic tyrosine-phosphorylated receptors, cell-surface proteins found mainly on immune cells. Its major role is being an integral component for the initiation of a variety of signaling pathway and subsequently the activation of immune cells, although different functions have been described, for example an osteoclast maturation.

Structure The motif contains a tyrosine separated from a leucine or isoleucine by any two other amino acids, giving the signature YxxL/I. Two of these signatures are typically separated by between 6 and 8 amino acids in the cytoplasmic tail of the molecule (YxxL/Ix(6–8)YxxL/I). However, in various sources, this consensus sequence differs, mainly in the number of amino acids between individual signatures. Apart from ITAMs which have the structure described above, there is also a variety of proteins containing ITAM-like motifs, which have a very similar structure and function (for example in Dectin-1 protein).

Function

ITAMs are important for signal transduction, mainly in immune cells. They are found in the cytoplasmic tails of non-catalytic tyrosine-phosphorylated receptors such as the CD3 and ζ-chains of the T cell receptor complex, the CD79-alpha and -beta chains of the B cell receptor complex, and certain Fc receptors. The tyrosine residues within these motifs become phosphorylated by Src family kinases following interaction of the receptor molecules with their ligands. Phosphorylated ITAMs serve as docking sites for other proteins containing a SH2 domain, usually two domains in tandem, inducing a signaling cascade mediated by Syk family kinases (which are the primary proteins that bind to phosphorylated ITAMs), namely either Syk or ZAP-70, resulting mostly in the activation of given cell. Paradoxically, in some cases, ITAMs and ITAM-like motifs do not have an activating effect, but rather an inhibitory one. Exact mechanisms of this phenomenon are as of yet not elucidated. Other non-catalytic tyrosine-phosphorylated receptors carry a conserved inhibitory motif (ITIM) that, when phosphorylated, results in the inhibition of the signaling pathway via recruitment of phosphatases, namely SHP-1, SHP-2 and SHIP1. This serves not only for inhibition and regulation of signalling pathways related to ITAM-based signalling, but also for termination of signalling.

Genetic variations Rare human genetic mutations are catalogued in the human genetic variation databases which can reportedly result in creation or deletion of ITIM and ITAMs.

Examples Examples shown below list both proteins that contain the ITAM themselves and proteins that use ITAM-based signalling with the help of associated proteins which contain the motif. CD3γ, CD3δ, CD3ε, TYROBP (DAP12), FcαRI, FcγRI, FcγRII, FcγRIII, Dectin-1, CLEC-1, CD28, CD72

References

Worked examples

Example 1 — a first encounter with Immunoreceptor tyrosine-based activation motif

Start with the simplest possible case. Write down what Immunoreceptor tyrosine-based activation motif 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 Immunoreceptor tyrosine-based activation motif 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 Immunoreceptor tyrosine-based activation motif 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 Immunoreceptor tyrosine-based activation motif

In research: Immunoreceptor tyrosine-based activation motif 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 Immunoreceptor tyrosine-based activation motif 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: Immunoreceptor tyrosine-based activation motif is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cell signaling, Immune system, so understanding it makes those chapters shorter.
In everyday life: Look for Immunoreceptor tyrosine-based activation motif 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.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Immunoreceptor tyrosine-based activation motif” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Immunoreceptor tyrosine-based activation motif in 20 minutes

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

Frequently asked questions

What is Immunoreceptor tyrosine-based activation motif in simple terms?

Why does Immunoreceptor tyrosine-based activation motif 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 Immunoreceptor tyrosine-based activation motif?

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 Immunoreceptor tyrosine-based activation motif.