science

Uterine serpin

Uterine serpin is a science 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 Uterine serpin rather than just read about it. In short: Uterine serpins are members of the A clade of the serine protease inhibitor (serpin) superfamily of proteins and are encoded by the SERPINA14 gene. Uterine serpins are produced by the endometrium of a restricted group of mammals under the influence of progesterone or estrogen.

Key takeaways

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

Reference excerpt

Uterine serpins are members of the A clade of the serine protease inhibitor (serpin) superfamily of proteins and are encoded by the SERPINA14 gene. Uterine serpins are produced by the endometrium of a restricted group of mammals under the influence of progesterone or estrogen. These proteins appear to be inactive protease inhibitors and may function during pregnancy to regulate immune function or participate in transplacental transport.

Nomenclature Uterine serpins were originally described in the uterine secretions of unilaterally-pregnant sheep as a pair of 57 kDa and 55 kDa glycoproteins. Termed uterine milk proteins, their identification as members of the serpin superfamily was based on sequencing of the cDNA for the sheep gene. The pig uterine serpin was first identified because of its association with an iron-binding uterine protein termed uteroferrin. and was originally termed uteroferrin-associated protein. The designation of uterine serpins as SERPINA14 is based on their classification as a highly-divergent group of the α1-antitrypsin or A clade. In other analyses, uterine serpins have been considered as a separate clade in the serpin superfamily.

Evolution The uterine serpins are novel with respect to other serpins by virtue of their limited distribution among mammals. They have been described only in species of the Laurasiatheria superorder of eutherian mammals. Among the clades in which uterine serpin genes exist are the Cetartiodactyla (dolphin, cow, water buffalo, sheep, goat, pig), Perissodactyla (horse) and some carnivores (dog, giant panda) The uterine serpin gene is not expressed in all carnivores since the only uterine serpin identified in the cat is a pseudogene. Examination of completed genomes indicates that uterine serpin genes do not exist in primates, mouse, rat, rabbit, marsupials, platypus, chicken or zebrafish.

Cellular expression and hormone regulation Uterine serpins are products of the endometrial epithelium (Figure 1). Gene expression is limited to epithelial cells of endometrial glands. Late in pregnancy, uterine serpin protein can be found in the lumenal epithelium as well, perhaps as glandular epithelial cells move to the uterine lumen. The major regulator of uterine serpin gene expression is progesterone. In the cow, estrogen can also increase uterine serpin gene expression. In addition to expression in the endometrium, bovine uterine serpin is also expressed in the ovary (follicles, corpus luteum, and cumulus-oocyte complex) and by cotyledons Archived 2010-06-24 at the Wayback Machine of the placenta.

Protease inhibitory activity There are two lines of evidence to indicate that uterine serpins do not function as protease inhibitors. Uterine serpins from the sheep and pig are not inhibitory towards a variety of proteases. In addition, several key amino acids in the hinge region of the reactive center loop which are important for protease inhibitory activity have not been conserved in uterine serpins. Bovine uterine serpin does inhibit pepsin but probably through a mechanism distinct from the prototypical mechanism used by serpins.

Function during pregnancy There are two possible biological roles for uterine serpins during pregnancy. The first is as a binding protein. Porcine uterine serpin binds non-covalently to uteroferrin in a way that stabilizes the iron-binding capacity of uteroferrin. Uteroferrin is transferred across the placenta where it gives up its iron to fetal transferrin. Ovine uterine serpin binds pregnancy-associated glycoproteins, which are inactive aspartic proteases secreted in large amounts by the ungulate placenta. Ovine uterine serpin also binds to activin, IgM and IgA. Another possible role for uterine serpins is in the inhibition of immune cell proliferation during pregnancy to provide protection for the allogeneically-distinct conceptus. In particular, sheep uterine serpin can inhibit lymphocyte and natural killer cell function in vitro and reduce natural-killer cell mediated abortion in a mouse model.

Genetics A single nucleotide polymorphism at position 1269 of the bovine uterine serpin gene has been associated with productive life in cattle populations.

Worked examples

Example 1 — a first encounter with Uterine serpin

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

In research: Uterine serpin appears in science 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 Uterine serpin 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: Uterine serpin is common in secondary-school and first-year university syllabi. It links to neighbouring topics Fertility, Hormones of the ovary, Hormones of the pregnant female, so understanding it makes those chapters shorter.
In everyday life: Look for Uterine serpin 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 Uterine serpin in 20 minutes

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

Frequently asked questions

What is Uterine serpin in simple terms?

Why does Uterine serpin matter?

Because it connects several science 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 Uterine serpin?

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 Uterine serpin.