This web page was produced as an assignment for Genetics 564, an undergraduate capstone course at UW-Madison.
What are protein domains?
Protein domains are distinct portions of a polypeptide chain or protein. Usually, they are responsible for a distinct function, however, structurally similar domains can be found in proteins with different functions. Protein domains of specific proteins may be conserved among homologous species. [1]
Domains Found in StAR
START Domain
START (StAR-related lipid-transfer) is a lipid-binding domain in StAR. This domain is critical for StAR's cholesterol transport function, perhaps through the binding of it. Following the discovery of the START domain in StAR (also known as STARD1), 14 additional START-domain-containing proteins were subsequently identified in vertebrates (termed STARD2 through STARD15). Additionally, thousands of other proteins containing at least one START domain have been found in invertebrates, bacteria, and plants that bind different substances such as sterols and lipids. [2]
Conservation of Domains in StAR
Conclusion
The conservation of protein domains among different species can provide insight into the significance of the domain's function. StAR is highly conserved among the homologs depicted above which highlights the importance of the domain in StAR's function of steroidogenesis initiation. This suggests that it may function by binding cholesterol during StAR's cholesterol transport activity but this is not known for certain. Further investigation into the exact role START plays in StAR function is still needed.
References
[1] What are protein domains? Retrieved March 14, 2019 from https://www.ebi.ac.uk/training/online/course/introduction-protein-classification-ebi/protein-classification/what-are-protein-domains
[2] START domain. Retrieved March 14, 2019 from http://pfam.xfam.org/family/PF01852.19
[1] What are protein domains? Retrieved March 14, 2019 from https://www.ebi.ac.uk/training/online/course/introduction-protein-classification-ebi/protein-classification/what-are-protein-domains
[2] START domain. Retrieved March 14, 2019 from http://pfam.xfam.org/family/PF01852.19
Header image: https://hipwallpaper.com/protein-backgrounds/