Centrioles: You Can't Divide Cells Without Them

By: Jesslyn Shields  | 
Centrioles, found in most eukaryotic cells, are organelles, typically arranged in a cylinder containing nine microtubule triplets composed of a protein called tubulin. Stocktrek Images/Getty Images

Cells are full of organelles — busy little structures that carry out specific jobs within the cell. Some organelles are similar in all multi-celled organisms, but one cell structure, centrioles, are found almost exclusively in animal cells [source: National Library of Medicine].

Present in a range of human cells including the early embryo and the sperm cell, these little cylindrical structures resemble a piece of Twizzler licorice candy, and are composed of a hollow tube made up of smaller tubes (centrioles are made up of a protein called tubulin). Centrioles come in handy when a cell duplicates itself through the process of mitosis.


A cell's centrioles are housed in the centrosome, which is basically a mass of proteins where the centrioles hang out, but which has its own role in cell division as well. All animal cells have two centrioles — a mother centriole and a daughter centriole — which are positioned at right angles to each other.

Cell Division 101

Cell division is tricky business: each and every aspect of the cell must be replicated perfectly, and since the centrioles play such an important role in this duplication, they duplicate themselves first. Once the two centrioles turn into four (and the single centrosome replicates itself), the rest of the cell is ready to divide.

The centrioles begin to migrate away from each other to opposite ends of the cell, like spindles casting thread-like tubules behind them as they travel. The centrosomes have all the proteins needed to make the microtubule threads, and later, when the cell's chromosomes duplicate, they follow the threads left by the centrioles to their new cell homes, partly under the direction of the centrosomes.


This artist's rendering of an animal cell shows a pair of centrioles and its position within the cell.
lvcandy/Getty Images

The Role of Centrioles in Cytokinesis

The cell cycle is a series of carefully coordinated steps that a cell undergoes, culminating in the division into two genetically identical daughter cells. This cycle is the very essence of biological continuity, underlying the growth and reproduction of all eukaryotic organisms.

Cytokinesis, the final phase of cell division, is orchestrated with precision, and centrioles play a pivotal role. Post mitosis, the cell’s cytoplasm divides, creating two daughter cells, each with its own complete set of organelles.


Centrioles, having duplicated, ensure that each new cell inherits a centrosome, setting the stage for spindle formation in the next cell cycle. This is crucial for maintaining genomic integrity and cellular function across generations of cells. Any error in centriole duplication or segregation can lead to numerous pathological conditions, including cancer.

Centrioles and the Cell Cycle

Throughout the first cell cycle, centrioles are fundamental in coordinating cellular events. During interphase, centrioles are involved in organizing the microtubule network, which is essential for maintaining cell shape, organelle distribution, and intracellular transport.

As the cell enters the mitotic phase, centrioles assist in the meticulous assembly of the mitotic spindle, the apparatus that segregates duplicated chromosomes. Centrioles' positioning and timing of duplication are meticulously controlled by a suite of regulatory proteins, ensuring that the cell’s blueprint is accurately replicated and distributed.


Centrioles in Health and Disease

Centrioles may be small, yet they are mighty in influence, especially when it comes to human health. Their misregulation is implicated in ciliopathies, a group of diseases resulting from defects in cilia, which centrioles help to form.

Moreover, centriole over-duplication is often observed in cancer cells, leading to abnormal cell division and tumor formation. Understanding the mechanisms of centriole replication and function is, therefore, pivotal in developing therapeutic strategies.


Novel cancer treatments are being explored that target the proteins responsible for centriole biogenesis (aka centriole formation) and function, offering hope in the fight against cancer [source: Science Direct].

Evolutionary Perspective of Centrioles

Centrioles are an evolutionary marvel, appearing in a diverse array of organisms and hinting at a common ancestral origin. Their structural complexity and the conservation of their associated proteins across species suggest an early appearance in the history of eukaryotic cells [source: National Library of Medicine].

Intriguingly, while indispensable in animal cells, centrioles are absent in higher plants and fungi, hinting at alternative mechanisms of cell division and structural support. This variance across life forms provides a rich tapestry for exploring the evolutionary pressures that have shaped cellular architecture and division.


Centrioles in Cellular Organization and Dynamics

Centrioles are not merely bystanders in cellular dynamics; they are conductors of cellular organization. By anchoring microtubules, they establish cell polarity—a fundamental feature of cellular differentiation and spatial orientation. Furthermore, centrioles influence the behavior of cells, guiding migratory patterns crucial in development and wound healing.

In neurons, centrioles are implicated in the establishment of axonal processes, underpinning the complex wiring of the nervous system. The study of centrioles, thus, extends beyond cell division, encompassing the broader principles of cellular architecture and dynamics that govern life at the microscopic level.


Wrapping Up

The centriole, a seemingly simple cylindrical structure, is a cornerstone of cellular function and integrity. As we have explored, its roles extend far beyond its participation in cell division.

Understanding the intricate dance of centrioles within the cell holds the key to unlocking mysteries of human biology and disease. Thus, while they may be minute in size, centrioles' impact on the biological tapestry is colossal, underscoring the elegance and complexity of cellular life.


The study of centrioles continues to be a vibrant and critical field, with each discovery offering new insights into the fundamental processes that sustain life as we know it.

This article was updated in conjunction with AI technology, then fact-checked and edited by a HowStuffWorks editor.