Protein sorting is the transportation of proteins by the cell either to organelles or outside of the cell

Protein sorting is the transportation of proteins by the cell either to organelles or outside of the cell. The understanding of protein sorting led to the finding of sorting signals and the signal hypothesis (Settembre et al. 2013). The signal hypothesis is the idea that secreted proteins have a specific amino acid sequence that determines where that protein will be localized/sorted. The amino acid sequence varies depending on the intended location of the protein. The discovery of protein sorting signals has paved the way for a greater understanding of protein functionality and localization. By understanding the protein localization we can determine patterns in normal and abnormal behavior. Proteins with identifying amino acid sequences (signal peptides) are produced in the endoplasmic reticulum (ER) during translation. These proteins are then sent to the appropriate organelle in the endomembrane system or outside of the cell. Examples of endomembrane system organelles include the Golgi apparatus or lysosomes. This signal peptide sequence acts as a tag and is located on either the C’ or N’ terminal of a peptide molecule. The C’ terminal is named so because it is the end of the peptide molecule that contains a carboxyl group. The N-terminal is the end of the amino group (Short, 2017).

Experiment

In an experiment to determine the functionality of a protein, protein sorting should be the target. Changes in the mechanism of protein sorting will cause displacement/mislocalization of proteins. For this experiment, an enzymatic lysosomal protein will have altered sorting (Brix, 2005). To begin the experiment the protein must first be identified, in this case, lysosomal proteases will be the target. This step is followed by identifying the native tag (amino acid sequence) of lysosomal proteases. After the tag is identified it should be eliminated and replaced with a different tag. It is this step that causes the mislocalization of the protein. Once mislocalized the lysosomal protease will be absent in lysosomal cells. Projected outcomes should be listed and compared with the experiment results. The lysosomal protease was picked for the experiment because its functions are commonly known. Two functions of lysosomal protease are its role in protein degradation and antigen processing. The absence of protease will cause reduced protein degradation, antigen processing, and lysosomal activity (Cooper, 2020). Proteins provide energy and amino acids when degraded. Protease is also essential to antigen processing. Antigen processing is the immunological process that presents antigens to T-cells (white blood cells); this is a part of adaptive immunity. I would assume that deficiencies in lysosomal protease would greatly hinder adaptive immune responses and amino acid production (Cooper, 2020). If decreased levels of amino acids and compromised immunity are long-lasting the health issues expected are chronic illness, constant fatigue, lowered alertness, and neurotransmitters imbalance. All organs can be affected an example is the brain, the brain can be affected by neurotransmitter imbalance which can lead to depression (not a physical presenting illness but still a life-threatening one). The significant health repercussions caused by the mislocalization of one protein are a testament to how much purpose every part of the body has. Nothing is without design or purpose; A verse that comes to mind is Proverbs 16:4.

Works Cited

Blobel, G., & Dobberstein, B. (1975). Transfer of proteins across membranes. I. Presence of proteolytically processed

and unprocessed nascent immunoglobulin light chains on membrane-bound ribosomes of murine myeloma. The

Journal of cell biology, 67(3), 835–851. https://doi.org/10.1083/jcb.67.3.835

Brix, K. (2005). Lysosomal proteases. In Lysosomes (pp. 50-59). Springer, Boston, MA.

Cooper GM (2020). The Cell: A Molecular Approach. 2nd edition. Sunderland

(MA): Sinauer Associates. Protein Degradation. Available from:

https://www.ncbi.nlm.nih.gov/books/NBK9957/

Proverbs 16:4 The LORD Has Made Everything for His Purpose–Even the Wicked

for the Day of Disaster., biblehub.com/proverbs/16-4.htm.

Settembre, C., Fraldi, A., Medina, D. L., & Ballabio, A. (2013). Signals from the lysosome: a

control center for cellular clearance and energy metabolism. Nature reviews. Molecular cell biology, 14(5), 283–296. https://doi.org/10.1038/nrm3565

Short B. (2017). The signal hypothesis matures with age. The Journal of Cell Biology, 216(5),

1207. https://doi.org/10.1083/jcb.201704081