biology

SPMIP4

SPMIP4 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 SPMIP4 rather than just read about it. In short: Sperm-associated microtubule inner protein 4 is a protein that in humans is encoded by the gene SPMIP4 (previously C7orf31). The SPMIP4 protein is predicted to be part of the core (axoneme) of the sperm flagellum.

Key takeaways

SPMIP4 belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect SPMIP4 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of SPMIP4 from memory before moving on to harder problems.

Reference excerpt

Sperm-associated microtubule inner protein 4 is a protein that in humans is encoded by the gene SPMIP4 (previously C7orf31). The SPMIP4 protein is predicted to be part of the core (axoneme) of the sperm flagellum.

Gene/Locus In humans, the SPMIP4 gene is located at the locus 7p15.3 and stretches between position 25174316 and 25219817 (span 45502 bp). It codes for at least 4 unique human isoforms: the primary isoform (590 aa; also denoted X1, X2, and CRA_c), isoform X4 (346 aa), isoform CRA_a (580 aa), and isoform CRA_b (380 aa).

Transcript In humans, SPMIP4 codes for an mRNA strand that is 3609 base pairs long. The human mRNA is composed of a 5' untranslated region that is 561 bases and a 3' untranslated region that is 1275 bases long.

Protein The primary protein encoded by SPMIP4 in humans is 590 amino acids long with molecular weight 38334 Da. The protein is part of a functionally uncharacterized family of proteins (pfam15093) with a domain of unknown function (DUF4555).

Protein Orthology The SPMIP4 protein is well-conserved in mammals and birds, but is less conserved in more distant organisms. SPMIP4 does not have any paralogs in humans.

Expression In humans, SPMIP4 is predicted to be localized in the cytosol, nucleus, mitochondrion, and peroxisome, and it is expressed in almost all tissues. It is highly expressed especially in the testes.

Interaction Two-hybrid studies have found interactions between the proteins encoded by A8K5H9 and SPMIP4, and another study has found the protein to interact with KBTBD5. A study in 2014 found SPMIP4 to be a candidate as a centrosome-associated protein, using mass spectrometry on mammalian sperm cells’ centrioles. The protein appears in the study alongside seven other centrosome-associated protein candidates. Along with 2241 other proteins, SPMIP4 also exhibited significant binding in a microarray experiment to β-amyloids, a group of proteins associated with Alzheimer's disease. Finally, in a protein-protein interaction network study, SPMIP4 was found to associate with KLHL40, whose exact function is also not known.

References

External links Human C7orf31 genome location and C7orf31 gene details page in the UCSC Genome Browser.

Illustrations

Worked examples

Example 1 — a first encounter with SPMIP4

Start with the simplest possible case. Write down what SPMIP4 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 SPMIP4 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 SPMIP4 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 SPMIP4

In research: SPMIP4 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 SPMIP4 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: SPMIP4 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Genes on human chromosome 7, Human chromosome 7 gene stubs, Uncharacterized proteins, so understanding it makes those chapters shorter.
In everyday life: Look for SPMIP4 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 SPMIP4 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what SPMIP4 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 SPMIP4 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is SPMIP4 in simple terms?

Why does SPMIP4 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 SPMIP4?

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 SPMIP4.