Cell Migration And Cell Cytoskeleton Biology Essay

The cytoskeleton of any cell plays a essential role in handling the moves of the cell. 3 types of fibres form this structure; microtubules, microfilaments and intermediate filaments. Microtubules are large hollow fibres, microfilaments will be the smallest at only '6nm in diameter' (1) and intermediate filaments are among.

Microtubules are developed from the subunits α - tubulin and β - tubulin, which form dimers. Each tubulin dimer includes 1 α - tubulin subunit and 1 β - tubulin subunit. These then polymerise to form long protofilaments, which become a member of together into sheets. Once a sheet of 13 protofilaments has been produced, they then flip over to produce a hollow microtubule, which is constantly on the elongate from the +ve end where only β - tubulin subunits are showing.

Microfilaments are made of a proteins subunit called actin. You will find two types; G - actin and F - actin. G - actin is switched in to F - actin by the hydrolysis of ATP, forming a fibrous filament. The actin filament continues to elongate from the -ve barbed end.

There are several types of Intermediate filaments, each manufactured from different proteins depending on the function of the cell where they are contained. Type I Keratins acidic and Type II Keratins basic are located in epithelial cells and in the scalp and fingernails or toenails. Nuclear lamins are found in the nuclear lamina and type III vimentin/desmin/peripherin are located in muscle cells, some neurones and stem cells (2). The monomers form dimers by coiling. Tetramers are then developed from dimers organized in staggered creation with contrary domains collectively. These then organize together developing strong coiled filaments.

'Many skin cells move by crawling over surfaces' (3). In the three fibrous constructions, explained previously that define a cell, the microfilaments play the greatest part in the movements and migration of an cell. Which means that actin is the vital part for cell activity. A fibroblast crawls by a leading protrusion, called a lamellipodium, which is where most of the cell's actin is situated. The actin is extremely flexible scheduled its twisted, connected structure. The filaments clump / package together near to the cell membrane, specifically at the protrusions including the microvilli within an intestine lining epithelial cell. The actin penetrates into the cytoplasm, ' where they become cross - connected directly into a three dimensional meshwork, governing the condition and mechanised properties of the plasma membrane and the cell surface. ' (4). Which means that the actin provides structural support, as well as movements potential for the cell. Filopodia are extremely comparable to lamellipodia. They also protrude out from the key body of the cells like lamellipodia, and act like hands for the cell to 'feel' the environment around it and also to aid the detection of where the cell is meant to migrate to. Filopodia have almost the same composition as lemellipodia, however have smaller protrusions and for that reason contain less actin. 'They are about 0. 1 m large and between 5 - 10 m long, and each consists of a loose pack of 10 - 20 actin filaments, orientated using their positive ends pointing outward'(5), exactly like the orientation of the actin filaments in lamellipodia. However, filopodia can be found around the whole circumference of the cell, not simply protruding from the lamellipodium, which creates a straight larger surface area for the cell to find its area. The protrusions 'grow' by the growth of the actin filaments, where dimers are added to the positive terminals of the filaments. Although dimers are removed from both terminals, particularly the negative end, this is outweighed by the faster addition of actin at the positive end. The development is an extremely quick process, which therefore allows the cells to move around your body at a fairly fast pace. Once the lamellipodium is protruded from the main structural form of the cell, the newly produced bottom section of the cell then adheres to the top it is moving along, hence pulling the rest of the cell along with it. At the same time, 'contraction occurs guiding the cell, then draws the body of the cell onward, in the route the lamellipodium is protruding, in a process called traction force. ' (6)

Cell migration is extremely important to the organism's survival. It is essential for the motion of skin cells in the disease fighting capability, an example of which is a macrophage, which locates destructive skin cells and 'eats' them. It is because it is essential for cells to be able to travel to the site of contamination in order to battle it and clear it up or to talk to other cells, to tell them that there is a problem, which they can then straighten out. Skin cells that can do that are called 'fibroblasts, which migrate through connective cells, remodelling them where necessary and helping to rebuild damaged set ups. ' (7). If this is extremely hard, the organism would be in serious trouble and could die or be terribly broken by very superficial wounds and moderate diseases that are overlooked as non-serious in humans credited to cells being able to migrate. The cell migration system is essential to a macrophage, as its job is to go around your body, detecting and destroying harmful cells. If movements had not been possible, the macrophage would only have the ability to detect destructive skin cells that were situated in the immediate vicinity, which means to successfully remove all hazardous pathogens would be impossible. This would indicate the organism would have very little coverage against disease.

Cells can also migrate by means apart from by lamellipodium protrusions. Cilia are one example, as well as a male human's sperm, which moves by way of a tail like composition called a flagellum. The sperm is able to overcome the flagellum, which is 'designed to go the entire cell, and rather than generating an up-to-date, they propagate regular waves along their duration that propel and drive the cell through water' (8). Unlike most other migrating skin cells in the human body as described above, the key component for activity in flagella is tubulin. Microtubules course the whole amount of the flagellum in an axoneme, 'which contains two central microtubules that are surrounded by an outside wedding ring of nine pairs of microtubules. ' (9). The motion is enabled by 'molecules of ciliary dyenin that form bridges between neighbouring microtubules about the circumference of the axoneme. ' (10) The end tail of one molecule attaches to a microtubule, while its other end, the top of the molecule attaches to some other microtubule. This stimulates a sliding mechanism similar compared to that of actin in the migration of cells with lamellipodium protrusions.

Bacteria and cilia also have flagella, manufactured from flagellin and dynein. The bacterial flagellum has a similar framework to a microtubule in the manner that it's a hollow, tube - like condition. 'Ciliary defeating can either propel single cells by having a substance or can move substance over the surface of several cells in a tissue' (11). The second reason is obvious in the human the respiratory system, where ciliated respiratory epithelium cells in the trachea prevent any overseas, potentially pollutants such as particles and bacteria in the air from stepping into the bronchioles and lungs. They do that by acting like very small hairs and by defeating the saliva filled with the harmful particles less difficult the trachea to exit the nasal cavities by coughing. In case the cilia are unable to beat, it causes problems such as Kartagener's syndrome or principal ciliary dyskinesia. Although this syndrome is extremely unusual, this can be a genetic disorder, interpretation it is hereditary. Due to the respiratory system having little to no defence against dirt and pathogens which enter into the nasal cavities and then travel down the trachea and bronchi, pollutants may type in the lungs. This causes illness and disease of the lungs, such as pneumonia or bronchitis.

In conclusion, the presence of cell migration mechanisms in organisms as small as bacteria to the top, multi - cellular microorganisms such as humans is extremely vital with their individual success. Without this important ability, skin cells would not have the ability to detect or deal with disease, from small superficial impediments to very serious diseases. Duplication in humans would not be possible and bacterias would find it extremely difficult to invade host cells for reproduction. Without cell migration, the complete human disease fighting capability would not be able to function correctly. Even though movement of cells is quite complicated, it is merely the beginning of a massive series of mechanisms in which cells can talk to one another to orchestrate the right workings of the human body.

Also We Can Offer!

Other services that we offer

If you don’t see the necessary subject, paper type, or topic in our list of available services and examples, don’t worry! We have a number of other academic disciplines to suit the needs of anyone who visits this website looking for help.

How to ...

We made your life easier with putting together a big number of articles and guidelines on how to plan and write different types of assignments (Essay, Research Paper, Dissertation etc)