Rsad1, also known as radical SAM domain-containing 1, is a member of the radical S-adenosylmethionine (SAM) enzyme family. Radical SAM enzymes catalyze complex reactions, yet the specific function of Rsad1 was initially unknown [1]. Rsad1 may be involved in pathways related to methionine usage and radical-based reactions, as its expression impacts these processes [4].

A study on chronic central serous chorioretinopathy (cCSC) found a significant association between Rsad1 and female cCSC patients. After exome sequencing and analysis, the gene-based tests showed that Rsad1 had significant associations in female cCSC patients but not in the entire cohort or male patients, suggesting a potential role of Rsad1 in female-specific cCSC susceptibility [2]. Additionally, the human Rsad1 was found to stably bind heme, indicating it could be a heme chaperone like its bacterial orthologue HemW, which is involved in inserting heme into respiratory chain enzymes [3].

In conclusion, Rsad1 has potential functions in heme-related processes and may be associated with female-specific cCSC. The findings from these studies contribute to understanding the biological functions of Rsad1, especially in relation to certain disease conditions, and highlight its importance in further in-vivo functional studies, potentially using gene knockout or conditional knockout mouse models to explore its role in more detail.

References:

1. Landgraf, Bradley J, McCarthy, Erin L, Booker, Squire J. 2016. Radical S-Adenosylmethionine Enzymes in Human Health and Disease. In Annual review of biochemistry, 85, 485-514. doi:10.1146/annurev-biochem-060713-035504. https://pubmed.ncbi.nlm.nih.gov/27145839/

2. Schellevis, Rosa L, Breukink, Myrte B, Gilissen, Christian, de Jong, Eiko K, den Hollander, Anneke I. 2019. Exome sequencing in patients with chronic central serous chorioretinopathy. In Scientific reports, 9, 6598. doi:10.1038/s41598-019-43152-3. https://pubmed.ncbi.nlm.nih.gov/31036833/

3. Haskamp, Vera, Karrie, Simone, Mingers, Toni, Jahn, Martina, Jahn, Dieter. 2017. The radical SAM protein HemW is a heme chaperone. In The Journal of biological chemistry, 293, 2558-2572. doi:10.1074/jbc.RA117.000229. https://pubmed.ncbi.nlm.nih.gov/29282292/

4. York, Audra, Everhart, Angela, Vitek, Michael P, Gottschalk, Kirby W, Colton, Carol A. . Metabolism-Based Gene Differences in Neurons Expressing Hyperphosphorylated AT8- Positive (AT8+) Tau in Alzheimer's Disease. In ASN neuro, 13, 17590914211019443. doi:10.1177/17590914211019443. https://pubmed.ncbi.nlm.nih.gov/34121475/