Centriole duplication is a tightly regulated process that occurs once per cell cycle. It begins at the G1-S transition phase.
The Process of Centriole Duplication
The process initiates when a new daughter centriole, called a procentriole, starts growing at a right angle (orthogonally) from the proximal end of each of the two existing centrioles, known as mother centrioles. These mother centrioles already exist within the cell. This procentriole then elongates throughout the S and G2 phases of the cell cycle.
- G1-S Transition: Procentriole formation begins.
- S and G2 Phases: Procentrioles elongate.
Daughter centrioles, initially termed procentrioles, are unable to duplicate themselves. Only mother centrioles can initiate the formation of new procentrioles. This ensures that centrioles duplicate only once per cell cycle.
The duplication process involves many proteins, and disruptions to these can lead to incomplete or abnormal centriole duplication. For example, deficiencies in proteins like CPAP can result in incomplete centrioles that still attempt to duplicate.
Importance of Regulated Duplication
The precise timing and control of centriole duplication are vital for accurate cell division. Errors in this process can lead to abnormal numbers of centrioles, potentially causing cellular dysfunction and contributing to diseases like cancer.
