Proper regulation of the Transforming Growth Factor-beta (TGF-b) pathway is important for maintaining homeostasis and development in various tissues across vertebrates and invertebrates. When TGF-b pathway signaling is disrupted it leads to tumor growth, birth defects, and other diseases. The identification and study of the various regulatory methods utilized within TGF-b pathway signaling is important to aid the understanding of disease prognosis and prevention. In the TGF-b pathway in Drosophila, dCORL functions in the dActivin subpathway and acts as a regulator of dSmad2 in the larval brain. dCORL is encoded by a gene on the fourth chromosome, in Drosophila. To learn more about dCORL’s role in the pathway, two fourth chromosomes were created that allow clonal analysis to be conducted. Clonal analysis is needed to determine dCORL’s role in TGF-b regulation in the adult brain. In my first project, both chromosomes were successfully created. Though, the importance of understanding regulatory mechanisms goes past one protein. In my second project, multiple conserved prodomain cysteines were identified in human amino acid alignments of 33 TGF-b family proteins across the three TGF-b subfamilies. Database mining identified conserved prodomain cysteine mutations in 10 proteins and their mutant phenotypes. Common phenotypes for conserved cysteine mutations suggest new heterodimer pairs. The most frequent mutant phenotypes associated with new heterodimers were tumors. Conserved prodomain cysteine mutations were connected to cysteine mutations in known regulatory partner proteins by mutant phenotype, yielding numerous new regulatory interactions. The most frequent mutant phenotypes connecting new regulatory interactions between TGF-b proteins and regulatory partners proteins were tumors. Together, my projects expand knowledge of regulatory mechanisms within the TGF-b pathway in Drosophila and humans, while providing hypotheses for further investigation.