1. Online Counseling Resource YCMOU ELearning Drive… School of Architecture, Science and Technology Yashwantrao Chavan Maharashtra Open University, Nashik – 422222, India

2. OC-SBT082-U01-03 Introduction Programmes and Courses  SBT082 –CP01- Unit 01

3. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.3 Credits  Academic Inputs by Arun Punaji More. M.Sc. (Microbiology) ‏ Experience: 11 Years arunmesh@hotmail.com

4. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.4 How to Use This Resource  Counselor at each study center should use this presentation to deliver lecture of 40-60 minutes during Face-To-Face counseling.  Discussion about students difficulties or tutorial with assignments should follow the lecture for about 40-60 minutes.  Handouts (with 6 slides on each A4 size page) of this presentation should be provided to each student.  Each student should discuss on the discussion forum all the terms which could not be understood. This will improve his writing skills and enhance knowledge level about topics, which shall be immensely useful for end exam.  Appear several times, for all the Self-Tests, available for this course.  Student can use handouts for last minutes preparation just before end exam.

5. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.5 Learning Objectives  After studying this module, you should be able to: Describe the intermediate filaments. Describe interactions of intermediate filaments with other proteins in forming cytoskeletons in the cells. Describe the functions of intermediate filaments

6. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.6 Introduction  In the formation of tissues the relative positions of cells are fixed and have to be maintained.  To maintain these positions in the tissue, there must be some mechanical support to be provided to each cell so that they would not move from their position in the tissue.  The protein filaments which provide these mechanical strength and support to each cell in the tissue are intermediate filaments.

7. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.7 Intermediate Filaments-1  These types of filaments are of dimension which lie in between the dimensions of actin and microtubule filaments; therefore they are called as intermediate filaments.  The intermediate filaments have diameter of 10nm.  Intermediate filaments are made of with variety types of proteins.

8. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.8 Intermediate Filaments-2  Types of proteins of intermediate filaments:- Acidic keratins, ---type I Basic keratins, ----type II Vimentin, ----------type III Neurofilament proteins, --------type IV Nuclear lamins ------------type V Nestins --------------------type VI

9. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.9 Intermediate Filaments-3  The intermediate filaments are grouped on the basis of these types of proteins from which they are made of with.  For example type I and type II are made of with acidic keratins and basic keratins.  Type I and type II intermediate filaments are most abundant in cytoplasm of epithelial cells.

10. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.10 Structure of Intermediate Filaments  All the intermediate filaments are alpha helical polypeptide chain made of with 310 to 350 amino acids.  The N-terminal of this polypeptide chain is called as head.  The C-terminal of this polypeptide chain is called as tail.  Unlike the actin and microtubule filaments, intermediate filaments are non polar, namely they do not have + and - ends.

11. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.11 Structure of Intermediate Filament  Structure of intermediate filament:- Steps in the formation of intermediate filament.

12. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.12 Characteristics of Intermediate Filament  The intermediate filaments are more stable than actin and microtubule filaments.  They are not dynamic like actin ant microtubule filaments.  Within cells they are frequently modified by assembly and disassembly by the process of phosphorylation.

13. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.13 Functions of Intermediate Filament  For example the phosphorylation of nuclear lamins results into disassembly of nuclear lamins and finally breakdown of nuclear membrane in mitosis.  The intermediate filaments provide mechanical stability to tissues.  For example the keratin filaments are firmly anchored into the special region of plasma membrane known as desmosomes and hemidesmosomes.

14. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.14 Functions of Intermediate Filament-2  In the epithelial cells of epithelial layer, the keratin filaments anchored to the both sides of desmosomes of adjacent cells forming a mechanical links between the adjacent cells in epithelial layer providing mechanical stability to the tissue.

15. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.15 Functions of Intermediate Filament-3  The intermediate filaments, desmin, in muscle tissues connect the individual actin-myosin assemblies both to one another and to plasma membrane, collectively enhancing the action of individual contractile desmin bundles.

16. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.16 Functions of Intermediate Filament-4  The neurofilaments which are major intermediate filaments in matured neuron provides support and stabilize the other types of cytoskeleton filaments in the delicate long thin axons of nerve cells.

17. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.17 Critical Thinking Questions  What role the intermediate filaments play in the cell division?

18. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.18 Hints for Critical Thinking Questions  They are present in the nuclear membrane.

19. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.19 Study Tips  Book Title: Title:The Cell, A Molecular Approach Author: Geoffrey M. Cooper, Robert E. Hausman Publication: ASM press, Washington,D.C. Publication: ASM press, Washington,D.C.  Book Title: Cell and Molecular Biology Title: Cell and Molecular Biology Author: E.D.P. De Robertis and E.M.F. De Robertis, Jr. Author: E.D.P. De Robertis and E.M.F. De Robertis, Jr. Publication: Lippincott and Williams & Wilkins Publication: Lippincott and Williams & Wilkins

20. End of the Presentation Thank You !