Centrosome - Introduction, History, Components, Functions

Introduction to Centrosome

Centrosome is a cell organelle that provides structure for the cell and is present only in the metazoan lineage of eukaryotic cells and lacks in plant and fungal cells.

In an animal cell, it serves as the main microtubule organizing center and regulator of cell-cycle progression. Although centrosomes are an important component in mitosis in animal cells, it is not mandatory in flies and flatworm species.

In plants and fungi, its function is replaced by other organelles.

History of Centrosome

The cell organelle centrosome was discovered by German biologist and founder of cytogenetics Walther Flemming in 1875 and was reported again in 1876 by Belgian embryologist, cytologist, and marine biologist Edouard Van Beneden.

In 1888, it was described and named by German zoologist, anatomist, and co-founder of modern cytology Theodor Boveri.

Components of Centrosome

Centrosomes are composed of two centrioles which are arranged at right angles to each other. It is surrounded by pericentriolar material (PCM) which is a dense, highly structured mass of protein. These proteins including γ-tubulin, pericentrin, and ninein are responsible for microtubule nucleation as well as anchoring.

Each centriole of the centrosome contains centrin, cenexin and tektin.

Functions of Centrosome

The centrosome is associated with the prophase stage of the cell cycle. After the nuclear membrane breaks down during mitosis, the centrosome-nucleated microtubules interact with chromosomes to build the spindle apparatus called the mitotic spindle.

During cell division, the centrosome is copied only once per cell cycle. Thus, each daughter cell inherits one centrosome that contains two structures called centrioles. The mother centriole accumulates materials required for assembling the daughter centriole.

Centrosomes are required for the survival of cells and hence organisms. Cells lacking centrosomes have an absence of astral microtubules.

It aids in cell division as it increases efficacy.

In humans, the sperm provides the centriole that creates the centrosome as well as the microtubule system of the zygote.