The cytoskeleton is a network of fibers throughout the cell's cytoplasm that helps the cell maintain its shape and gives support to the cell. It is a cellular scaffolding or skeleton contained within the cytoplasm, present in both eukaryotes and prokaryotes. It is a dynamic structure that maintains cell shape, often protects the cell, enables cellular motion (using structures such as flagella, cilia and lamellipodia), and plays important roles in both intracellular transport (the movement of vesicles and organelles, for example) and cellular division.
The eukaryote cytoskeleton is composed of three different types of fibres: microtubules, microfilaments and intermediate filaments, which are differentiated by their size, with microtubules being the thickest and microfilaments being the thinnest. Microfilaments are solid rods made of globular proteins called actin and are common to all eukaryotic cells. Microfilaments range from 5 to 9 nanometers in diameter and are designed to bear large amounts of tension. In association with myosin, microfilaments help to generate the forces used in cellular contraction and basic cell movements.
The filaments also enable a dividing cell to pinch off into two cells and are involved in amoeboid movements of certain types of cells. Intermediate filaments, 8 to 12 nanometers in diameter, are more stable (strongly bound) than actin filaments, and heterogeneous constituents of the cytoskeleton. They are prominent in cells that withstand mechanical stress and are the most insoluble part of the cell. Each intermediate filament monomer consists of an alpha helical rod domain which coils around another filament like a rope to form a dimer.
The intermediate filaments are classified into five types: Types I-Acidic Keratin, Types II-Basic Keratin, Type III intermediate filaments are distributed in a number of cell types, including vimentin in fibroblasts, endothelial cells and leukocytes; desmin in muscle; glial fibrillary acidic factor in astrocytes and other types of glia, and peripherin in peripheral nerve fibers, Type IV-Neurofilament H (heavy), M (medium) and L (low), Type IV-internexin and Type V are the lamins which have a nuclear signal sequence so they can form a filamentous support inside the inner nuclear membrane. Microtubules, the third principal component of the cytoskeleton, are rigid hollow rods approximately 25 nm in diameter. Like actin filaments, microtubules are dynamic structures that undergo continual assembly and disassembly within the cell. Microtubules are composed of a single type of globular protein, called tubulin which is a dimer consisting of two closely related 55-kd polypeptides, alpha-tubulin and beta-tubulin.
In addition, a third type of tubulin (gamma-tubulin) is specifically localized to the centrosome, where it plays a critical role in initiating microtubule assembly. Tubulin dimers polymerize to form microtubules, which generally consist of 13 linear protofilaments assembled around a hollow core. The protofilaments, which are composed of head-to-tail arrays of tubulin dimers, are arranged in parallel. Microtubules function both to determine cell shape and in a variety of cell movements, including some forms of cell locomotion, the intracellular transport of organelles, and the separation of chromosomes during mitosis.
Apart from eukaryotes, the prokaryote cytoskeleton consists of various proteins like FtsZ, MreB, ParM and crescentin which are involved in the maintenance of cell shape.
Article Tags: cytoskeleton
IMGENEX India Pvt Ltd. the only biotech company in Orissa and one of its kinds in Eastern India. IMGENEX India started in Oct as an outsourcing branch of IMGENEX Corporation, San Diego, USA. Find out more information about Cytoskeleton.
Related Articles on Medicine
- Medicine
by Saqib Ansari
Medicine is a branch of health science and the sector of public life concerned with maintaining or r... - Branches of Medicine
by Saqib Ansari
Working together as an interdisciplinary team, many highly trained health professionals besides medi... - Development of symptoms in diabetes
by Saqib Ansari
In type 1 diabetes the symptoms tend to develop more quickly, over a couple of weeks, and are more s... - New research in Bird Flu Virus
by Saqib Ansari
Three recent papers in the New England Journal of Medicine illustrate serious roadblocks to understa... - Drug Rehab Treatment
by Ira
Choosing a drug rehab treatment center is a decision that calls for both negative and positive emoti... - Plastic Surgery in Brazil
by Vincent CHASTEL
Estetica Brasil, established in Fortaleza, is one of the premier Plastic Surgery company in Brazil, ... - Why consider Brazil for cosmetic surgery?
by Vincent CHASTEL
Brazil is located in South America and is the largest Latin American country and the fifth largest c... - Plastic Surgery in Brazil – Making The Right Choice
by Vincent CHASTEL
The past few years have seen a dramatic change in the public perception of plastic surgery, leading ... - Plastic and Cosmetic Surgery in Brazil and Baby Boomers.
by Vincent CHASTEL
A bulge of Baby Boomers, men and women, come through the doors of plastic surgeons in Brazil, willin... - Medical Tourism : What is it ?
by Vincent CHASTEL
Why are hundreds of thousands of people traveling overseas every year to receive plastic surgery or ... - Explore a better opportunity with cosmetic surgery at Brazil
by Vincent CHASTEL
Thousands of people go under the knife for the sake of beauty each year. A little nip here, a little... - Medical tourism in Brazil get a new face with booming plastic surgery treatments
by Vincent CHASTEL
The world is coming to Brazil to have its wrinkles stretched and its tummy tucked. In 2006, 50,000 f... - About Urinary Tract Infection - Prevention and Treatments
by Knut Holt
About causes and symptoms of urinary tract infection. Also about standard treatment, lifestyle meas... - About Common Cold and Influenza and the Difference between These Two Ailments
by Knut Holt
Common cold and influenza (flu) give many of the same symptoms, and they are often mistaken for each... - Joint Pain
by Sudhani k
Joint Pain - The word arthritis literally means joint inflammation, but it is often used to refer to... - IMGENEX has now p73 phosphospecific antibody
by Stephen Jones
The p53 family member, p73, also known as tumor protein 73 (TP73) has been recently identified as a ... - Stem Cell Factor (SCF)- The c-kit ligand
by Stephen Jones
Hematopoiesis is governed by a number of cytokines that promote the survival, proliferation, and dif... - China's Pharmaceutical Actuality and Future
by Angulo Fu
In the past twenty years, China's pharmaceutical market has an averaging between 18 - 20% growth, si... - Anaphylaxis Causes
by David Done
Anaphylaxis is a serious allergic reaction that occurs in response to a particular trigger. Knowing ... - Anaphylaxis Food Allergies
by David Done
A food allergy is an immune response to a food that the body mistakenly thinks is harmful and then r... - Pros and Cons of Plastic Surgery
by David Done
Pros and Cons of Plastic Surgery - Not everyone is blessed with perfect skin, a cute nose or perky b... - How to Cure or Alleviate Edema, including Lymphedema
by Knut Holt
Lifestyle changes and other simple methods to treat edema are presented and the working mechanisms o... - How to Cure Constipation and Hemorrhoids
by Knut Holt
Some simple measures to cure constipation and hemorrhoids are presented. The working mechanisms of e... - About Yeast Infection and Candidiasis - Prevention and Treatments
by Knut Holt
About causes and symptoms of yeast infection. Also about standard treatment, lifestyle measures and ... - Guide to Buying Medications Online
by Peter
Are you aware of the possible dangers of buying medicines online? Find out how to safeguard yourself...
