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The purpose of proteins

Proteins are essential for life, and there are many different types with many different functions. Examples include structural proteins, which maintain the integrity of the cell, transporter proteins responsible for facilitating the movement of substances in, out and around the cell, and enzymes responsible for catalysing specific biochemical reactions.

Examples of proteins

  • Insulin is an example of a protein that functions as a hormone and regulates the glucose levels in the blood.
  • Haemoglobin is an example of a transporter protein, as it carries oxygen around the body.

The role of RNA in protein production

RNA is crucial for protein production. As DNA cannot leave the nucleus the relevant sections are transcribed into messenger RNA (mRNA) and transported to the ribosomes where proteins are produced. At the ribosome, transfer RNA (tRNA) facilitates the addition of the correct amino acids to the polypeptide chain which ultimately becomes the protein. The ribosomes themselves are formed of proteins and ribosomal RNA (rRNA).

An additional type of RNA, known as signal recognition particle RNA (SRP RNA), is involved in the control of translation and sorting of membrane and secreted proteins.

RNA sequencing

By sequencing RNA, it is possible to establish which genes are actively producing proteins and which are not. This can be useful in identifying aberrant gene activity and potential drug targets to inhibit or enhance gene activity to alter gene expression, and therefore protein production.

Key messages

  • Proteins are essential for life, and the human body has over 100,000 different proteins performing many different functions.
  • RNA is crucial for protein production, with several types involved.
  • RNA sequencing can be used to identify aberrant gene activity and potential drug targets.


For clinicians

Tagged: Core concepts

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  • Last reviewed: 09/05/2022
  • Next review due: 09/05/2024
  • Authors: Dr Ed Miller
  • Reviewers: Dr Siobhan Simpson