Essential Cell Biology 5th edition

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Contents
CHAPTER 17
Cytoskeleton 573
INTERMEDIATE FILAMENTS 575
Intermediate Filaments Are Strong and Ropelike 575
Intermediate Filaments Strengthen Cells Against Mechanical Stress 577
The Nuclear Envelope Is Supported by a Meshwork of Intermediate Filaments 578
Linker Proteins Connect Cytoskeletal Filaments and Bridge the Nuclear Envelope 579
MICROTUBULES 580
Microtubules Are Hollow Tubes with Structurally Distinct Ends 581
The Centrosome Is the Major Microtubule-organizing Center in Animal Cells 581
Microtubules Display Dynamic Instability 582
Dynamic Instability Is Driven by GTP Hydrolysis 583
Microtubule Dynamics Can Be Modified by Drugs 584
Microtubules Organize the Cell Interior 584
Motor Proteins Drive Intracellular Transport 586
Microtubules and Motor Proteins Position Organelles in the Cytoplasm 587
Cilia and Flagella Contain Stable Microtubules Moved by Dynein 590
ACTIN FILAMENTS 592
Actin Filaments Are Thin and Flexible 593
Actin and Tubulin Polymerize by Similar Mechanisms 593
Many Proteins Bind to Actin and Modify Its Properties 594
A Cortex Rich in Actin Filaments Underlies the Plasma Membrane of Most Eukaryotic
Cells 596
Cell Crawling Depends on Cortical Actin 596
Actin-binding Proteins Influence the Type of Protrusions Formed at the Leading Edge 598
Extracellular Signals Can Alter the Arrangement of Actin Filaments 598
Actin Associates with Myosin to Form Contractile Structures 599
MUSCLE CONTRACTION 600
Muscle Contraction Depends on Interacting Filaments of Actin and Myosin 600
Actin Filaments Slide Against Myosin Filaments During Muscle Contraction 601
Muscle Contraction Is Triggered by a Sudden Rise in Cytosolic Ca 2+ 604
Different Types of Muscle Cells Perform Different Functions 605
ESSENTIAL CONCEPTS 606
QUESTIONS 607