Centrosome

Centrosome: Overview, Structure, Functions, Diagram

Edited By Irshad Anwar | Updated on Jul 02, 2025 05:54 PM IST

The centrosome is an organelle found in animal cells that functions as the cell's microtubule-organising centre. It also helps to regulate the cell cycle. A centrosome consists of two centrioles. Centrosome is a topic of the chapter Cell: The Unit of Life in Biology.

What are Centrosomes?

The centrosome is the structure of the cell that was most accurately identified with the help of these markers. The microtubule organising centre also called the centrosome, is one of the most important structures in the cell; it is responsible for cell shape control, and microtubule orientation to form a proper network and accurate cell division.

This Story also Contains

What are Centrosomes?
Structure of Centrosomes
Functions of Centrosomes
Centrosome Cycle
Centrosomes in Different Organisms
Centrosome Related Diseases and Disorders
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Centrosome: Overview, Structure, Functions, Diagram

It is made up of two centrioles enclosed by a matrix of proteins; the centrosome plays the role of making sure that the chromosomes split properly during mitosis. First identified in the 1800s by Theodor Boveri and Edouard van Beneden, the role of the centrosome in organising the cell and dividing it continues to be seen as crucial to cell biology.

Structure of Centrosomes

The structure of centrosomes is given below:

Centriole Pair

Detailed structure:

A typical centrosome houses two centrioles which are cylindrical structures that have nine microtubule triplets within a cartwheellike formation. These triplets produce a frame for the formation of microtubules and are involved in the process of ciliogenesis and flagellogenesis.

Centriole

Pericentriolar Material (PCM)

Composition and role:

Around the centrioles, there exists pericentriolar material which is a dense proteinaceous material containing among other components gamma-tubulin, pericentrin, and others. PCM is involved in the nucleation and the anchoring of microtubules since it offers the correct conditions for microtubule elongation.

Centrosome Matrix

Functions of Centrosomes

The functions of centrosomes are discussed below:

Microtubule Organization

One of the significant components of the PCM is the centrosome matrix from which the cell’s MTOC is derived. It controls the formation and addition of microtubules and maintains the cell integrity, vehicular transport, and sometimes the mitotic spindle of the cells.

Microtubule Nucleation and Anchoring:

The Centrosome is the main MTOC of animal cells organizing the network of microtubules that gives structural support and also plays a role in the transport of particles.

Cell Division

Role in mitosis and meiosis:

Not only that, it initiates the formation of new microtubules, besides organizing and strengthening them in the cell. Similarly, the centrosome also duplicates and sets as the poles of the mitotic spindle that are scattered throughout the chromatids accurately.

Formation of the mitotic spindle:

It also directs the formation of the mitotic spindle: this is a structure that is composed of microtubes and is instrumental in the separation of chromosomes to the daughter cells in mitosis and meiosis.

Cell Cycle Regulation

Centrosome cycle and its coordination with the cell cycle:

Centrosome cycling, which includes duplication and maturation, is well-regulated with another cell cycle so that each daughter cell contains one centrosome to retain the order and functionality of a cell.

Intracellular Transport

Role in the trafficking of vesicles and organelles:

The centrosome helps in the transport of vesicles and organelles within a cell by aligning the tracks formed by microtubules, where molecular motors transport the structures to their required destinations with the help of the tracks, thus assisting in intracellular transport.

Centrosome Cycle

The centrosome cycle is discussed below:

Duplication

Centrosome replication takes place at the beginning of the S phase and results in the duplication of the centrosomes to two by the time the cell begins to divide. This process is controlled strictly by the proteins involved in the cell cycle like cyclins and cyclin-dependent kinases to avoid the mistakes that can cause abnormal cell division and aneuploidy.

Separation

In prophase, the centrosomes that have reproduced start to migrate and position themselves at the poles of the cell. This is spearheaded by motor proteins like the dynein and the kinesin that run along the microtubules. By the end of metaphase, the centrosomes ensure that they are located at the spindle poles where they aid in the formation of the mitotic spindle that enables the segregation of chromosomes.

Function in Cytokinesis

The centrosomes need to be positioned correctly and to function in cytokinesis in which the cells are divided into halves by the breakup of the cytoplasm to create two daughter cells. They assist in the organization of the contractile ring and the cleavage furrow that is required for the proper separation of daughter cells thereby increasing the chances of cell division success.

Centrosomes in Different Organisms

The following describes the centrosome in different organisms:

Animal Cells

The animal cell centrosomes are generally present and include two centrioles surrounded by pericentriolar material (PCM). It is the main microtubule organizing center also known as centrosome and plays a significant role in cell division and organization. It can also manifest itself in different types of cells and at different stages of its development as a result of functional needs.

Plant Cells

Unlike animal cells, plant cells do not contain centrosomes and unipolar spindles of plant cells extend from each pole during cell division. Nonetheless, it involves other microtubule organizing centre (MTOCs) scattered all over the cell. They are centrosomes which are analogous to MTOCs and they help in the organization of microtubules as well as proper cell division The nuclear surface is usually a site of microtubule nucleation during mitosis.

Yeast and Other Eukaryotes

Thus, based on the described characteristics, it is found that yeast cells do not contain centrosomes, whereas their MTOCs are known as the spindle pole bodies (SPBs). Thus, in other eukaryotes, different centrosomes or structurally and functionally similar organelles may be present depending on the organism’s necessities. Such adaptations show how different species provide different solutions to the problems of assembling microtubules and dividing the cell.

Centrosome Related Diseases and Disorders

The disorders are discussed below:

Cancer

Centrosome hyperplasia, the state in which cells contain more than two centrosomes, is manifested in cancer very frequently. It can cause defects in spindle formation, chromosome segregation, and antisepsis which are responsible for tumorigenesis and cancer development.

Microcephaly

The improper regulation of some genes that are involved in centrosome duplication and function also hit human beings leading to microcephaly, a situation where an individual has a small brain. These mutations interfere with cell division and the development of the brain which in turn results in serious neurological complications.

Other Disorders

Abnormality of the centrosome can also underlie other diseases including ciliopathies as well. Centrosomes are involved in the formation and function of cilia and if this structure is affected through defects in proteins associated with the centrosome the functions of cilia are affected leading to diseases like polycystic kidney disease, respiratory diseases, and retinal degeneration.

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Frequently Asked Questions (FAQs)

1. What is the function of a centrosome in a cell?

The centrosome in a cell is mostly involved with the manipulation of microtubules and the management of a cell cycle. It is the principal structure required for nucleation of microtubules necessary in the maintenance of cell form, movement of organelles and objects within the cell, and information of the spindle during mitosis.

2. How do centrosomes contribute to cell division?

Centrosomes play an important role in prokaryotic and eukaryotic cell division since the microtubules are used during mitosis and meiosis anchored by the centrosomes. They initiate and orchestrate the formation of the mitotic spindle which is important in the correct division of chromosomes into the newly formed daughter cell.

3. How do centrosomes contribute to cell division?

Centrosomes contribute to cell division by organizing the mitotic spindle. During prophase, the two centrosomes move to opposite poles of the cell and initiate the formation of microtubules that will eventually attach to and separate the chromosomes.

4. Describe the structure of centrosome?

The main structures that form a centrosome include two centrioles; they are cylindrical structures that consist of microtubule triplets. Around the centrioles, there is the pericentriolar material or PCM, which is a proteinaceous matrix dense composed of various proteins attached to microtubules and involved in the control of its polymerization and depolymerization.

5. How does centrosome duplication occur during the cell cycle?

Centrosome replication happens during the cell division cycle in association with longitudinal DNA synthesis in the S phase. Centrosome also duplicates and the two centrosomes are pulled apart and move to the proximal poles of the cell during mitosis. This process is very strictly controlled to achieve the correct course of the formation and operation of the mitotic spindle.

6. What diseases are associated with centrosome dysfunction?

Some of the diseases related to centrosomes include cancer; for instance, centrosome amplification is evident in cell lines and is associated with chromosome instability and tumor progression. Other associated genes include microcephaly, which is also associated with mutations that affect centrosome function in the formation of the brain; and ciliopathies which are characteristic of mutation that affects the ciliary function in the development of the brain.

7. How does the centrosome's structure change during the cell cycle?

During the cell cycle, the centrosome undergoes duplication. In G1 phase, there's one centrosome with two centrioles. During S phase, new centrioles begin to form. By G2 phase, there are two complete centrosomes, each with two centrioles, which will help form the mitotic spindle during cell division.

8. How do centrosomes replicate?

Centrosome replication begins during S phase of the cell cycle. New centrioles form perpendicular to the existing ones, growing throughout S and G2 phases. By the onset of mitosis, two mature centrosomes are present, each containing a pair of centrioles.

9. What is centrosome maturation and when does it occur?

Centrosome maturation is the process by which centrosomes increase in size and microtubule-nucleating capacity. It occurs during the G2 phase of the cell cycle, preparing the centrosomes for their role in mitotic spindle formation.

10. How do centriolar satellites contribute to centrosome function?

Centriolar satellites are small, granular structures that cluster around centrosomes. They play a role in protein trafficking to and from the centrosome, contributing to centrosome assembly, ciliogenesis, and regulation of centrosome-associated activities.

11. How do centrosomes contribute to asymmetric cell division?

In asymmetric cell division, centrosomes play a role in determining the axis of division and the unequal distribution of cellular components. The orientation and positioning of the mitotic spindle, organized by centrosomes, can influence which daughter cell receives specific cellular factors.

12. What is centrosome amplification and why is it significant in cancer biology?

Centrosome amplification refers to the presence of more than two centrosomes in a cell. This is significant in cancer biology because it can lead to multipolar spindles during mitosis, resulting in chromosome missegregation and genomic instability, which are hallmarks of many cancers.

13. What is the relationship between centrosomes and the cell cycle checkpoints?

Centrosomes are involved in cell cycle checkpoints, particularly the G2/M checkpoint. Abnormalities in centrosome number or structure can trigger this checkpoint, preventing cells with potential mitotic defects from entering division.

14. What is the role of centrosomes in neurodevelopment?

In neurodevelopment, centrosomes play crucial roles in neuronal migration, axon formation, and dendrite development. They help establish cell polarity in neurons and organize microtubules for proper neurite outgrowth and branching.

15. What is centrosome positioning and why is it important?

Centrosome positioning refers to the specific localization of the centrosome within a cell. It's important for determining the axis of cell division, establishing cell polarity, and directing intracellular transport. Proper positioning is crucial for normal cell function and tissue organization.

16. How do centrosomes contribute to cell migration?

Centrosomes contribute to cell migration by organizing the microtubule network, which is essential for cell polarization and directional movement. They often reorient towards the leading edge of migrating cells, facilitating the reorganization of the cytoskeleton.

17. Why don't plant cells typically have centrosomes?

Plant cells don't typically have centrosomes because they have evolved different mechanisms for organizing their microtubules. Instead of centrosomes, plant cells use dispersed microtubule organizing centers (MTOCs) located throughout the cell cortex to organize their microtubule network.

18. How do centrosomes differ between animal and fungal cells?

While animal cells typically have centrosomes containing centrioles, fungal cells have functionally similar structures called spindle pole bodies (SPBs). SPBs are embedded in the nuclear envelope and lack centrioles but still serve as the main microtubule organizing centers.

19. How do centrosomes contribute to the establishment of left-right asymmetry in developing organisms?

Centrosomes contribute to left-right asymmetry by influencing the formation and function of nodal cilia during early development. The orientation and beating of these cilia, organized by basal bodies derived from centrioles, create a directional fluid flow that helps establish left-right body axis.

20. How do centrosomes contribute to the formation of the immunological synapse?

In immune cells, centrosomes help organize the immunological synapse by repositioning to the area of cell-cell contact. This reorientation aids in the directed secretion of cytokines and lytic granules towards target cells.

21. What is the relationship between centrosomes and the Golgi apparatus?

Centrosomes and the Golgi apparatus are often closely associated in animal cells. The centrosome can influence Golgi positioning and organization, which is important for directed protein secretion and maintaining cell polarity.

22. What is the relationship between centrosomes and cilia or flagella?

Centrosomes, specifically the centrioles within them, can act as basal bodies for the formation of cilia or flagella. When a centriole migrates to the cell surface and attaches to the plasma membrane, it can serve as a template for the growth of the microtubule-based structure of a cilium or flagellum.

23. How do centrosomes contribute to cell polarity?

Centrosomes contribute to cell polarity by serving as a major microtubule organizing center. They help establish and maintain the asymmetric distribution of cellular components, which is crucial for processes like cell migration, differentiation, and tissue organization.

24. What is the function of γ-tubulin in centrosomes?

γ-tubulin is a crucial component of the pericentriolar material. It forms ring complexes that serve as templates for microtubule nucleation, essentially acting as a "seed" from which microtubules can grow.

25. What is a centrosome and why is it important in cell biology?

A centrosome is a cellular organelle found in animal cells that serves as the main microtubule organizing center (MTOC). It's important because it plays a crucial role in cell division, organizing the mitotic spindle during mitosis and meiosis, and helps maintain cell shape and polarity.

26. How many centrioles are typically found in a centrosome?

A typical centrosome contains two centrioles. These centrioles are cylindrical structures arranged perpendicular to each other, forming an L-shape configuration.

27. What is the primary structural component of centrioles?

The primary structural component of centrioles is tubulin. Specifically, centrioles are composed of nine triplets of microtubules arranged in a circular pattern, often described as a "9+0" arrangement.

28. What is pericentriolar material (PCM) and what is its function?

Pericentriolar material (PCM) is a protein-rich matrix surrounding the centrioles in a centrosome. It functions as the site for microtubule nucleation and anchoring, playing a crucial role in organizing the cell's microtubule network.

29. What is the composition of the pericentriolar material (PCM)?

The pericentriolar material (PCM) is composed of various proteins, including γ-tubulin, pericentrin, and centrosomin. These proteins work together to nucleate and anchor microtubules, forming a dynamic structure that can change in size and composition throughout the cell cycle.

30. How do centrosomes contribute to microtubule organization in interphase cells?

During interphase, centrosomes act as the primary microtubule organizing center in animal cells. They nucleate and anchor microtubules, creating a radial array that extends throughout the cytoplasm, influencing cell shape, organelle positioning, and intracellular transport.

31. What is the centrosome cycle and how does it relate to the cell cycle?

The centrosome cycle is the series of events involving centrosome duplication and separation, which occurs in coordination with the cell cycle. It ensures that each daughter cell receives one centrosome after cell division, maintaining the correct number of centrosomes per cell.

32. How do abnormalities in centrosome structure or number affect cell division?

Abnormalities in centrosome structure or number can lead to aberrant mitotic spindle formation, resulting in chromosome missegregation, aneuploidy, or multipolar divisions. These abnormalities are often associated with genomic instability and cancer.

33. What is the role of centrosomes in ciliogenesis?

Centrosomes, specifically the mother centriole, play a crucial role in ciliogenesis. The mother centriole can dock to the cell membrane and act as a basal body, serving as a template for the growth of the ciliary axoneme.

34. How do centrosomes contribute to the organization of the endoplasmic reticulum?

Centrosomes help organize the endoplasmic reticulum (ER) by nucleating and anchoring microtubules that the ER uses as tracks for its distribution throughout the cell. This organization is important for ER function and structure.

35. What is the relationship between centrosomes and cell size regulation?

Centrosomes play a role in cell size regulation by influencing mitotic spindle size and positioning. The size and microtubule-nucleating capacity of centrosomes can affect the size of the mitotic spindle, which in turn can influence the size of daughter cells after division.

36. How do centrosomes contribute to the DNA damage response?

Centrosomes are involved in the DNA damage response by serving as docking sites for various DNA repair proteins. They also play a role in activating cell cycle checkpoints in response to DNA damage, helping to maintain genomic stability.

37. What is centrosome clustering and why is it important in cancer cells?

Centrosome clustering is a mechanism by which cancer cells with supernumerary centrosomes can still undergo bipolar division. It's important because it allows cancer cells with centrosome amplification to survive and continue dividing, despite having an abnormal number of centrosomes.

38. What is the relationship between centrosomes and the nuclear envelope?

Centrosomes are typically closely associated with the nuclear envelope in interphase cells. During mitosis, they play a role in nuclear envelope breakdown and reformation. In some organisms, like fungi, centrosome equivalents (spindle pole bodies) are embedded in the nuclear envelope.

39. How do post-translational modifications of centrosomal proteins affect centrosome function?

Post-translational modifications of centrosomal proteins, such as phosphorylation, ubiquitination, and SUMOylation, can regulate centrosome duplication, maturation, and function. These modifications can affect protein-protein interactions, protein stability, and enzymatic activities within the centrosome.

40. What is the role of centrosomes in cellular senescence?

Centrosomes play a role in cellular senescence by influencing cell cycle progression and genomic stability. Senescent cells often show abnormalities in centrosome number or structure, which can contribute to the permanent cell cycle arrest characteristic of senescence.

41. How do centrosomes contribute to the organization of the actin cytoskeleton?

While centrosomes primarily organize microtubules, they also influence the actin cytoskeleton. They can serve as a site for actin nucleation and affect the distribution of actin-regulating proteins, contributing to overall cytoskeletal organization and cell shape.

42. What is the relationship between centrosomes and autophagy?

Centrosomes have been implicated in the regulation of autophagy, a cellular degradation process. They can serve as assembly sites for autophagy-related proteins and influence the formation of autophagosomes, linking cytoskeletal organization to autophagic processes.

43. How do centrosomes contribute to cell fate determination in stem cells?

In stem cells, centrosomes can influence cell fate by affecting the orientation of cell division and the asymmetric distribution of cellular components. The inheritance of the older or younger centrosome can sometimes correlate with different cell fates in daughter cells.

44. What is the role of centrosomes in intracellular signaling?

Centrosomes serve as important signaling hubs in cells. They can act as docking sites for various signaling molecules and kinases, integrating multiple cellular signals and influencing processes like cell cycle progression, stress response, and differentiation.

45. How do centrosomes contribute to the formation of the midbody during cytokinesis?

During cytokinesis, centrosomes organize the central spindle microtubules that form the midbody. The midbody is crucial for the final separation of daughter cells, and centrosome-derived materials are often found in the midbody structure.

46. What is the relationship between centrosomes and the p53 tumor suppressor pathway?

The p53 tumor suppressor pathway is linked to centrosome regulation. p53 can influence centrosome duplication and respond to centrosome abnormalities. Conversely, centrosome amplification can activate p53, triggering cell cycle arrest or apoptosis to prevent genomic instability.

47. How do centrosomes contribute to the organization of the mitochondrial network?

Centrosomes influence mitochondrial organization by nucleating and anchoring microtubules that serve as tracks for mitochondrial movement and positioning. This organization is important for proper mitochondrial function and distribution within the cell.

48. What is the role of centrosomes in meiosis compared to mitosis?

In meiosis, centrosomes play a similar role to mitosis in organizing the spindle apparatus. However, in meiosis I, they must organize a spindle that segregates homologous chromosomes rather than sister chromatids. In some organisms, centrosomes are eliminated during oogenesis and reformed after fertilization.

49. How do centrosomes contribute to the formation of primary cilia?

Centrosomes, specifically the mother centriole, are crucial for primary cilia formation. The mother centriole migrates to the cell surface, docks with the plasma membrane, and serves as the basal body from which the ciliary axoneme extends.

50. What is the relationship between centrosomes and cell cycle-regulated protein degradation?

Centrosomes are closely linked to cell cycle-regulated protein degradation. They serve as docking sites for various proteins involved in the ubiquitin-proteasome system, which is crucial for the timely degradation of cell cycle regulators and progression through different cell cycle phases.

51. How do centrosomes contribute to the organization of the nuclear pore complexes?

Centrosomes can influence the distribution of nuclear pore complexes (NPCs) in the nuclear envelope. The microtubule network organized by centrosomes can affect NPC positioning, which in turn can impact nucleocytoplasmic transport and nuclear organization.

52. What is the role of centrosomes in cellular stress responses?

Centrosomes play a role in cellular stress responses by serving as integration points for stress signaling pathways. They can influence cell cycle arrest, apoptosis, or stress granule formation in response to various cellular stresses, helping to maintain cellular homeostasis.

53. How do centrosomes contribute to the establishment of apical-basal polarity in epithelial cells?

In epithelial cells, centrosomes contribute to apical-basal polarity by influencing microtubule organization. Their positioning can affect the distribution of polarity proteins and the organization of junctional complexes, which are crucial for maintaining epithelial cell polarity.

54. What is the relationship between centrosomes and the spindle assembly checkpoint?

Centrosomes are involved in the spindle assembly checkpoint (SAC) by contributing to proper kinetochore-microtubule attachments. Abnormalities in centrosome number or function can activate the SAC, preventing cell division until proper attachments are achieved.

55. How do centrosomes contribute to the regulation of cell volume?

Centrosomes contribute to cell volume regulation by organizing the microtubule network, which influences cell shape and size. They also play a role in positioning organelles and regulating ion channels, which are important factors in maintaining proper cell volume.