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Small humanin-like peptide

Small humanin-like peptide 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 Small humanin-like peptide rather than just read about it. In short: Small humanin-like peptides (SHLPs) are a group of peptides encoded in the 16S ribosomal RNA region of mitochondrial genome. Six peptides of this group (SHLP1–6) have been identified so far, between 20-38 amino acids in length.

Small humanin-like peptide — main illustration
Small humanin-like peptide — illustration

Key takeaways

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

Reference excerpt

Small humanin-like peptides (SHLPs) are a group of peptides encoded in the 16S ribosomal RNA region of mitochondrial genome. Six peptides of this group (SHLP1–6) have been identified so far, between 20-38 amino acids in length. They are derived from the mitochondria and act as important retrograde signaling molecules in the cell. Their names were given because the SHLPs share some similar biological effects with the mitochondrial peptide Humanin. Every individual SHLP showed unique expression pattern in mouse tissues. Specifically, SHLP1 was detected in the heart, kidney, and spleen; SHLP2 was detected in the liver, kidney, and muscle; SHLP3 was detected in the brain and spleen; SHLP4 was detected in the liver and prostate; and SHLP6 was detected in the liver and kidney. Experiments using cultured mammalian cells have shown that SHLPs are bioactive peptides. Incubation of each synthetic SHLP with cells affected cell viability, proliferation and apoptosis differentially, which suggests that every SHLP may play a different role in the biological system.

Discovery An in silico search for potential small open-reading-frames (sORFs) within 16S ribosomal RNA-encoding short peptides (20–40 amino acids) was conducted in the Pinchas Cohen lab at University of Southern California. Six sequences encoding 20–38 amino-acid-long peptides were identified, which were named SHLP 1–6. The endogenous SHLPs were detected by immunoblots and their transcripts were validated by both qPCR and northern blot.

Structure All SHLPs, like humanin, are encoded in the mitochondrial 16S RNA gene (MT-RNR2). The human sequences are:

HN MAPRGESCLLLLTSEIDLPVKRRA S1 MCHWAGGASNTGDARGDVFGKQAG S2 MGVKFFTLSTREFPSVQRAVPLWTNS S3 MLGYNFSSFPCGTISIAPGENFYRLYFIWVNGLAKVVW S4 MLEVMELVNRRGKICRVPETFFNLSL S5 MYCSEVGFCSEVAPTEIFNAGLWV S6 MLDQDIPMVQPLLKVRLEND

Note that no formal HUGO gene symbols have been assigned to any of the SHLPs. They are not to be confused with the Shelphs, which are sometimes abbreviated SHLP in their gene symbol.

Functions Individual SHLPs demonstrated different biological effects. SHLP2 and SHLP3 enhanced cell viability and inhibited apoptosis in both NIT-1 and 22Rv1 cells. SHLP2 and SHLP4 promoted cell proliferation in NIT-1 β-cells. SHLP6 significantly increased apoptosis in both NIT-1 and 22Rv1 cells, having an effect opposite of SHLP2 and SHLP3. Moreover, SHLP2 and SHLP3 also induced oxygen consumption rate (OCR) and increased cellular ATP levels, which indicates that SHLP2 and 3 are mitochondrial modulators. Analysis of SHLP and humanin homologs across all vertebrates show that humanin and SHLP6 are well-conserved and subject to natural selection, suggesting that they have a biological function. SHLP4 is conserved but does not appear to be under selection.

See also MOTS-c

References

This article incorporates text by Laura J. Cobb, Changhan Lee, Jialin Xiao, Kelvin Yen, Richard G. Wong, Hiromi K. Nakamura, Hemal H. Mehta, Qinglei Gao, Carmel Ashur, Derek M. Huffman, Junxiang Wan, Radhika Muzumdar, Nir Barzilai, and Pinchas Cohen2 available under the CC BY 4.0 license.

Illustrations

Small humanin-like peptide: Locations of SHLPs in the mitochondrial genome
Locations of SHLPs in the mitochondrial genome

Worked examples

Example 1 — a first encounter with Small humanin-like peptide

Start with the simplest possible case. Write down what Small humanin-like peptide 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 Small humanin-like peptide 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 Small humanin-like peptide 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 Small humanin-like peptide

In research
Small humanin-like peptide 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 Small humanin-like peptide 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
Small humanin-like peptide is common in secondary-school and first-year university syllabi. It links to neighbouring topics Metagenomics, so understanding it makes those chapters shorter.
In everyday life
Look for Small humanin-like peptide 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 Small humanin-like peptide in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Small humanin-like peptide means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Small humanin-like peptide out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Small humanin-like peptide in simple terms?

Small humanin-like peptides (SHLPs) are a group of peptides encoded in the 16S ribosomal RNA region of mitochondrial genome. Six peptides of this group (SHLP1–6) have been identified so far, between 20-38 amino acids in length.

Why does Small humanin-like peptide 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 Small humanin-like peptide?

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 Small humanin-like peptide.

Tags

  • Metagenomics

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