Researchers at the University of California, San Diego School of Medicine have elucidated the role of a protein essential to regulating the progression of the cell cycle. Until recently, it assumed to promote development of cancer. Actually, it works to suppress the growth of tumors. Findings reported in the scientific journal eLife and recently covered by Science Daily show that cyclin-D, synthesized during the first stage of cell replication, is now believed to induce interactions with the retinoblastoma protein, otherwise known as Rb. Since we know that Rb acts as a tumor suppressor, mutilated and dysfunctional Rb is associated with several major cancers.
Scientists have long considered Cyclin-D has be a possible cause in the spread of cancer, as it hinders of the ability of Rb to suppress tumors through a process called phosphorylation. In the study, a team led by UC San Diego Department of Cellular and Molecular Medicine professor Steven F. Dowdy, took the effort to count the number of phosphates added to Rb during cell cycle progression. They began this process to discover how many single phosphates cyclin-D adds during the process. The results of their studies and observations found that cyclin-D adds one phosphate at one of the fourteen locations early along in the G1 phase of the cell cycle. This indicates that fourteen different versions of Rb tumor suppressors are created and instigated, thus enabling the activation of Rb.
The researchers believe these findings could change current understandings of the G1 cell cycle regulation, as well as the molecular origins of many of the common cancers affecting the general public today.