Investigating a Novel Type of Protein Degradation in Candida albicans

Candida albicans is the 4th most frequent hospital acquired infection worldwide and is known for targeting already compromised patients. It can grow as yeast cells, pseudohyphae, hyphae, or within a biofilm. The ability to form both hyphae and biofilms has been fundamentally linked to the disease causing potential of this organism and the way it grows is intimately related to the how it senses and reacts to its surrounding environment. One of the environmental factors known to stimulate filamentation, which also happens to be human body temperature, is grown at 37 degrees Celsius. Previous experiments studying protein changes in Candida albicans during filamentation at 37 degrees Celsius revealed a subset of proteins showing discordance between the levels of different peptides quantified from within the same protein. Deeper analysis suggested specific regions of these proteins with different quantitative differences when compared to the peptides from other regions of the same protein. The data from the discordance peptides suggested that those proteins might be degraded by a unique mechanism distinct from ubiquitin dependent protein degradation. To further study this we constructed two different strains to study proteins that represented this discordance, these being C4_00700c_a (Pho13) and Smt3. The parent was manipulated to contain the proteins with Myc tags added to the end of these proteins for the purpose of later being studied through Western Blot analysis. The Western Blot used antibodies to detect the tags and demonstrate the discordance of the individual protein at 37 and 30 degrees Celsius respectfully at time points of 1 and 3 hours, paralleling the observations from previous experiments. An ubiquitin inhibitor of dependent protein degradation was used to test the method by which these proteins were degrading. Our data correlated with the interesting finding from the previous experiments and denoted the importance of one of these proteins to filamentation. Further investigation should help shed light on this mechanism of regulatory filamentation