Cell Migration And Cell Cytoskeleton Biology Essay

Cell Migration And Cell Cytoskeleton Biology EssayThe cytoskeleton of a electric cubicleular ph one(a) plays a vital role in controlling the elbow greases of the cell. 3 types of fibres tier this structure microtubules, microfilaments and intermediate filaments. Microtubules be large hollow fibres, microfilaments atomic number 18 the smallest at lonesome(prenominal) 6nm in diameter (1) and intermediate filaments atomic number 18 in between.Microtubules be formed from the subunits tubulin and tubulin, which form dimers. Each tubulin dimer contains 1 tubulin subunit and 1 tubulin subunit. These then polymerise to form long protofilaments, which join together into sheets. once a sheet of 13 protofilaments has been formed, they then fold over to father a hollow microtubule, which continues to elongate from the +ve blockade where only tubulin subunits are showing.Microfilaments are made of a protein subunit called actin. There are two types G actin and F actin. G actin is turned 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(prenominal) types of Intermediate filaments, distributively made of different proteins depending on the function of the cell in which they are contained. Type I Keratins acidic and Type II Keratins basic are found in epithelial cells and in the whisker and nails. Nuclear lamins are found in the nuclear lamina and type deuce-ace vimentin/desmin/peripherin are found in muscle cells, some neurones and stem cells (2). The monomers form dimers by coiling. Tetramers are then formed from dimers arranged in staggered validation with oppo pose do of imports together. These then arrange together forming strong coiled filaments. umteen cells sound by crawling over erupts (3). Of the tercet fibrous structures, explained previously that make up a cell, the microfilaments play the largest part in the movement and migration of a cell. This operator that actin is the vital component for cell movement. A fibroblast crawls by a leading protrusion, called a lamellipodium, which is where most of the cells actin is located. The actin is exceedingly flexible repay equal to(p) its twisted, linked structure. The filaments clump / bundle together near the cell membrane, in particular at the protrusions much(prenominal) as the microvilli in an intestine lining epithelial cell. The actin penetrates in to the cytoplasm, where they become cross linked in to a three dimensional meshwork, governing the shape and mechanical properties of the plasma membrane and the cell surface. (4) . This means that the actin provides structural support, as well as movement potentiality for the cell. Filopodia are very similar to lamellipodia. They also protrude out from the main proboscis of the cells like lamellipodia, and act like fingers for the cell to feel the environment or so it and also to aid the detection of whe re the cell is supposed to migrate to. Filopodia have almost the exact same structure as lemellipodia, withal have smaller protrusions and therefore contain less actin. They are virtually 0.1 m wide and between 5 10 m long, and each contains a loose bundle of 10 20 actin filaments, orientated with their unequivocal ends pointing outward(5), exactly like the orientation of the actin filaments in lamellipodia. However, filopodia are present around the whole circumference of the cell, not just protruding from the lamellipodium, which creates an even larger surface area for the cell to detect its surroundings. The protrusions grow by the step-up of the actin filaments, where dimers are added to the positive terminals of the filaments. Although dimers are removed from both terminals, particularly the cast out end, this is outweighed by the more rapid addition of actin at the positive end. The result is a very quick process, which therefore allows the cells to move around the tr ee trunk at a fairly fast pace. Once the lamellipodium is protruded from the main structural shape of the cell, the newly produced bottom section of the cell then adheres to the surface it is moving along, hence pulling the rest of the cell along with it. At the same time, contraction occurs at the rear of the cell, then draws the body of the cell forward, in the direction the lamellipodium is protruding, in a process called traction. (6)Cell migration is extremely important to an beingnesss survival. It is essential for the movement of cells in the immune establishment, an example of which is a macrophage, which finds destructive cells and eats them. This is because it is vital for cells to be fitted to travel to the site of an infection in order to compete it and clear it up or to extend with other cells, to let them know that there is a problem, which they base then sort out. Cells that can do this are called fibroblasts, which migrate done connective interweave, remodell ing them where necessary and helping to rebuild damaged structures. (7). If this was not possible, the organism would be in serious trouble and could die or be badly damaged by very superficial wounds and mild diseases which are overlooked as non-serious in creation due to cells being qualified to migrate. The cell migration mechanism is vital to a macrophage, as its job is to move around the body, detecting and destroying bruising cells. If movement was not possible, the macrophage would only be able to detect destructive cells that were situated in the immediate vicinity, which means to successfully remove all harmful pathogens would be impossible. This would mean the organism would have very little protection against disease.Cells are also able to migrate by means other than by lamellipodium protrusions. Cilia are one example, as well as a male humans sperm, which moves by a tail like structure called a flagellum. The sperm is able to beat the flagellum, which is designed to m ove the entire cell, and instead of generating a current, they penetrate regular waves along their length that propel and drive the cell by means of liquid (8). Unlike most other migrating cells in the human body as described above, the main component for movement in flagella is tubulin. Microtubules cut through the whole length of the flagellum in an axoneme, which contains two central microtubules that are surrounded by an outer ring of nine pairs of microtubules. (9). The movement is enabled by molecules of ciliary dyenin that form bridges between neighbouring microtubules around the circumference of the axoneme. (10) The end tail of one molecule attaches to a microtubule, while its other end, the take of the molecule attaches to another microtubule. This promotes a sliding mechanism similar to that of actin in the migration of cells with lamellipodium protrusions.Bacteria and cilia also have flagella, made of flagellin and dynein. The bacterial flagellum has a similar struc ture to a microtubule in the way that it is a hollow, thermionic vacuum tube like shape. Ciliary trouncing can either propel whiz cells through a politic or can move fluid over the surface of a group of cells in a tissue (11). The second is apparent in the human respiratory system, where ciliated respiratory epithelium cells in the trachea prevent any foreign, potentially harmful particles such as dust and bacteria in the air from introduction the bronchioles and lungs. They do this by acting like tiny hairs and by beating the saliva containing the harmful particles back up the trachea to exit the cadaverous cavities by coughing. If the cilia are unable to beat, it causes problems such as Kartageners syndrome or elementary ciliary dyskinesia. Although this syndrome is extremely rare, it is a genetic disorder, meaning it is hereditary. Due to the respiratory system having little to no defence against dust and pathogens which visualise the penniless cavities and then travel down the trachea and bronchi, harmful particles may enter the lungs. This causes infection and disease of the lungs, such as pneumonia or bronchitis.In conclusion, the battlefront of cell migration mechanisms in organisms as small as bacteria to the large, multi cellular organisms such as humans is extremely vital to their individual survival. Without such an important ability, cells would not be able to detect or fight disease, from minor superficial impediments to very serious illnesses. Reproduction in humans would not be possible and bacteria would find it extremely demanding to invade host cells for reproduction. Without cell migration, the whole human immune system would not be able to function correctly. Although the movement of cells is quite complex, it is only the beginning of a massive sequence of mechanisms in which cells can communicate with each other to orchestrate the correct workings of the human body.