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

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

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

School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.4 How to Use This Resource  Counselor at each study center should use this presentation to deliver lecture of minutes during Face-To-Face counseling.  Discussion about students difficulties or tutorial with assignments should follow the lecture for about 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.

School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.5 Learning Objectives  After studying this module, you should be able to:  Describe what are cytoskeletons  Describe the various types of cytoskeletons present in cells  Describe the various functions of various types of cytoskeletons

School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.6 Introduction  Our body limbs move because of contraction and relaxation of skeleton muscles.  But do you know that cell also possess some kind of muscles to its various activities such as transport of cellular organelles in the cytoplasm, for cell division, for its own movement?  Yes cells possess the kind of muscles for its above mentioned activities and they are called as cytoskeleton.

School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.7 Cytoskeleton-1  Cytoskeleton is network of micro proteins filaments having dimensions of 7nm to 25 present in the cytoplasm.  it is dynamic structure that continuously organized.  The functions of cytoskeleton include  i) providing structural support to maintain the structural integrity of the cell.  ii) carrying out transport of cell organelles in the cytoplasm  iii) facilitate cell movement  iv) involvement in cell division

School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.8 Cytoskeleton-2  The cytoskeleton is made of three types of protein filaments which are  Actin filaments  Intermediate filaments  Microtubules

School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.9 Cytoskeleton-3  Actin filaments:-  The actin filaments are made of with a protein called as actin.  The actin proteins account for 5 to 10% of the total proteins in the eukaryotic cells.  The actin proteins can polymerize to form actin filaments.  The actin protein with association of actin binding proteins can assembled, disassembled and form bundles of actin filaments.

School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.10 Cytoskeleton-4  Actin filaments:- The actin-binding proteins involved in the formation of actin filaments or polymerization of actin monomers are  Apr2/3 complex proteins  ADF/cofilin proteins  Profilin proteins

School of Science and Technology, Online Counseling Resource… Cytoskeleton-5  Polymerization of actin proteins:-

School of Science and Technology, Online Counseling Resource… Cytoskeleton-5  Branching of actin filaments:- Arp2/3 and ATP molecules actively cause the branching of the actin Filament.

School of Science and Technology, Online Counseling Resource… Cytoskeleton-6  Formation of actin filament bundles and networks:-

School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.14 Cytoskeleton-5  Actin filaments:- The actin bundling proteins involved in formation of actin filaments bundles by cross linking the actin filaments are  Fimbrin  Alpha actinin  Filamin  Spectrin  Dystrophin  Integrin  Talin  vanculin

School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.15 Cytoskeleton-7  Molecular motors:- Molecular motors are the proteins that convert chemical energy in the form of ATPs into the mechanical energy. The molecular motors proteins get associated with cytoskeleton filaments and bring about their movement. The molecular motors proteins are  Myosins  Kenesins  Dyneins

School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.16 Cytoskeleton-6  The actin filaments are abundant beneath the plasma membrane forming a network of actin filaments, a cytoskeleton that  gives mechanical support to the plasma membrane,  determine cell shape,  allow cell surface movement required for food uptake, engulfment of particles and  cell migration.

School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.17 Cytoskeleton-7  Actin filaments:- The actin filaments cause muscle contractions. The actin-myosin contraction in non-muscle tissues involved in cytokinesis —cell division. Actin filaments cause cell movements, cell migration, movements in phagocytosis. Actin filaments are involved in extensions of nerve cells during nerve development.

School of Science and Technology, Online Counseling Resource… Cytoskeleton-8  Cytokinesis:- The actin filaments are Actively involved in the Separation of newly formed Daughter cells, a Process known as Cytokinesis.

School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.19 Cytoskeleton-8  Intermediate filaments:- Intermediate filaments are made of with variety of proteins polymers. The intermediate filaments have got diameter of 10 nm. The intermediate proteins are grouped into six types. The specific type of intermediate proteins are expressed in a type of cells. For example, the acidic keratin proteins are expressed in epithelial cell.

School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.20 Cytoskeleton-9  Intermediate filaments:- Types of intermediate proteins:-  Acidic keratins  Basic keratins  Vimentins  Desmins  Neurofilament proteins – NF-L, NF-M, NF-H, alpha internexin  Nuclear lamins  Nestins.

School of Science and Technology, Online Counseling Resource… Cytoskeleton-10  Structure of intermediate filaments:- Steps in formation of intermediate filament.

School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.22 Cytoskeletons-10  Intermediate filaments:- Functions-- The intermediate filaments are more stable than actin and microtubules filaments. The intermediate filaments strengthen the cytoskeletons of cells in the tissues enabling the cells to withstand any mechanical stress in the tissues. Keratin filaments provide mechanical strength to epithelial cells in the tissues. The intermediate filaments are responsible for the structures of number of tissues such as skin, intestine, skeleton muscle and heart which are subjected to mechanical stress.

School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.23 Cytoskeletons-11  Microtubules filaments:- These are hollow rigid rods of 25 nm in diameter made of with single type of globular protein polymer called as tubulin. Tubulin is dimer of alpha tubulin and β tubulin polypeptides. Like actin filaments the microtubule filaments are dynamic structures and assemble, dissemble constantly. The movements of microtubules is caused by the associations of motors molecules such as  Kinesin and dyneins

School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.24 Cytoskeletons-12  Microtubules filaments:- The main functions of the microtubule filaments are to maintain the cell shapes and cause variety of cell movements. They are involved in intracellular transport of organelles and separation of chromosomes during mitosis. They are responsible for the movements of cilia and flagella.

School of Science and Technology, Online Counseling Resource… Cytoskeleton-13  Separation of chromosomes during ana phase:-

School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.26 What We Learn…  The Definition of cytoskeletons  Chemical characteristics of cytoskeletons  Various types of cytoskeletons  Functions of cytoskeletons

School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.27 Critical Thinking Questions  What will be effects of defective actin filaments in the body?

School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.28 Hints For Critical Thinking Questions  The actin filaments are involved in structural stability as well as locomotion of cellular organelles.

School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.29 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

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