Sabtu, 25 Juni 2011

Intermediate Filaments

Ultrastructural and immunocytochemical investigations reveal that a third major filamentous structure is present in eukaryotic cells. In addition to the thin (actin) and thick (myosin) filaments, cells contain a class of intermediate-sized filaments with an average diameter of 10–12 nm (Figure 2–37 and Table 2–4). Several proteins that form intermediate filaments have been isolated and localized by immunocytochemical means.

Figure 2-37
Electron micrograph of a skin epithelial cell showing intermediate filaments of keratin associated with desmosomes.

Table 2–4. Examples of Intermediate Filaments Found in Eukaryotic Cells.
Filament Type Cell Type Examples
Keratins Epithelium Both keratinizing and nonkeratinizing epithelia
Vimentin Mesenchymal cells Fibroblasts, chondroblasts, macrophages, endothelial cells, vascular smooth muscle
Desmin Muscle Striated and smooth muscle (except vascular smooth muscle)
Gilial fibrillary acidic proteins Glial cells Astrocytes
Neurofilaments Neurons Nerve cell body and processes

Keratins (Gr. keras, horn) are a family of approximately 20 proteins found in epithelia. They are encoded by a family of genes and have different chemical and immunological properties. This diversity of keratin is related to the various roles these proteins play in the epidermis, nails, hooves, horns, feathers, scales, and the like that provide animals with defense against abrasion and loss of water and heat.
Vimentin filaments are characteristic of cells of mesenchymal origin. (Mesenchyme is an embryonic tissue.) Vimentin is a single protein (56–58 kDa) and may copolymerize with desmin or glial fibrillary acidic protein.
Desmin (skeletin) is found in smooth muscle and in the Z disks of skeletal and cardiac muscle (53–55 kDa).
Glial filaments (glial fibrillary acidic protein) are characteristic of astrocytes but are not found in neurons, muscle, mesenchymal cells, or epithelia (51 kDa).
Neurofilaments consist of at least three high-molecular-weight polypeptides (68, 140, and 210 kDa). Intermediate filament proteins have different chemical structures and different roles in cellular function.

Medical Application
The presence of a specific type of intermediate filament in tumors can reveal which cell originated the tumor, information important for diagnosis and treatment (see Table 1–1). Identification of intermediate filament proteins by means of immunocytochemical methods is a routine procedure.

Afzelius BA, Eliasson R: Flagellar mutants in man: on the heterogeneity of the immotile-cilia syndrome. J Ultrastruct Res 1979;69:43. [PMID: 501788]
Aridor M, Balch WE: Integration of endoplasmic reticulum signaling in health and disease. Nat Med 1999;5:745. [PMID: 10395318]
Barrit GJ: Communication Within Animal Cells. Oxford University Press, 1992.
Becker WM et al: The World of the Cell, 4th ed. Benjamin/Cummings, 2000.
Bretscher MS: The molecules of the cell membrane. Sci Am 1985;253:100. [PMID: 2416050]
Brinkley BR: Microtubule organizing centers. Annu Rev Cell Biol 1985;1:145. [PMID: 3916316]
Brown MS et al: Recycling receptors: the round-trip itinerary of migrant membrane proteins. Cell 1983;32:663. [PMID: 6299572]
Cooper GM: The Cell: A Molecular Approach. ASM Press/Sinauer Associates, Inc., 1997.
DeDuve C: A Guided Tour of the Living Cell. Freeman, 1984.
DeDuve C: Microbodies in the living cell. Sci Am 1983;248:74.
Dustin P: Microtubules, 2nd ed. Springer-Verlag, 1984.
Farquhar MG: Progress in unraveling pathways of Golgi traffic. Annu Rev Cell Biol 1985;1:447. [PMID: 3916320]
Fawcett D: The Cell, 2nd ed. Saunders, 1981.
KrstĂ­c RV: Ultrastructure of the Mammalian Cell. Springer-Verlag, 1979.
Mitchison TJ, Cramer LP: Actin-based cell motility and cell locomotion. Cell 1996;84:371. [PMID: 8608590]
Osborn M, Weber K: Intermediate filaments: cell-type-specific markers in differentiation and pathology. Cell 1982;31:303. [PMID: 6891619]
Pfeffer SR, Rothman JE: Biosynthetic protein transport and sorting in the endoplasmic reticulum. Annu Rev Biochem 1987;56:829. [PMID: 3304148]
Rothman J: The compartmental organization of the Golgi apparatus. Sci Am 1985;253:74. [PMID: 3929377]
Simons K, Ikonen E: How cells handle cholesterol. Science 2000;290:1721. [PMID: 11099405]
Tzagoloff A: Mitochondria. Plenum, 1982.
Weber K, Osborn M: The molecules of the cell matrix. Sci Am 1985;253:110. [PMID: 4071030]



This post was not only helpful but very useful too. Thank you for sharing this piece of your expertise with all of us. Cheers!


Your blog always create some informational and amazing things, which add in my knowledge

and experience.But I am a bit confuse. Thanks for sharing.Waiting for next post...


I have studied your site fully and I realized that, it is the most beneficial for us. I want to take more information through this site.

Adams Scott

"Thank you very much for the whole information.I agree with all the points mentioned here and noticed all your important points.
advertising | top advertising agencies in Pakistan | Marketing Agency | Advertisement

sherlina halim

Pengen yang lebih seru ...
Ayo kunjungi
Buktikan sendiri ..

Real Play = Real Money

- Bonus Promo Red Card pertandingan manapun .
- Bonus Mixparlay .
- Bonus Tangkasnet setiap hari .
- New Produk Sabung Ayam ( minimal bet sangat ringan ) .
- Referal 5 + 1 % ( seumur hidup ) .
- Cash Back up to 10 % .
- Bonus Royalty Rewards setiap bulan .

untuk Informasi lebih jelasnya silahkan hubungi CS kami :
- YM :
- WHATSAPP : +63 905 213 7234
- WECHAT : asianbet_77
- SMS CENTER : +63 905 209 8162
- PIN BB : 2B4BB06A / 28339A41

Salam Admin ,

Mobile App Developers

Nice post, things explained in details. Thank You.

UI UX Designers Delhi

This is the precise weblog for anybody who needs to seek out out about this topic. You notice so much its almost arduous to argue with you. You positively put a brand new spin on a subject that's been written about for years. Nice stuff, simply nice!

Posting Komentar

Posting Lebih Baru Posting Lama Beranda


Chat Box

Top Commentators

Give Me +1


Foto Saya
I created this blog just to support the activities of my learning about histology and others



Copyright © 2011 De Histology

Templates by Poncol Gate | CSS3 by David Walsh | Powered by {N}Code & Blogger