Copyright (c) by W. H. Freeman and Company Chapter 18 Cell Motility and Shape I: Microfilaments

Copyright (c) by W. H. Freeman and Company

Chapter 18

Cell Motility and Shape I: Microfilaments


18.1 The actin cytoskeleton

Actin filaments (or microfilaments) are one of the three protein filament systems that comprise the cytoskeleton

Eukaryotic cells contain abundant amounts of highly conserved actin

Figure 18-1


18.1 ATP holds together the two lobes of the actin monomer

Figure 18-2a


18.1 G-actin assembles into long, helical F-actin polymers

Figure 18-2b,c


18.1 The actin cytoskeleton is organized into bundles and networks of filaments

Figure 18-4


18.1 Actin cross-linking proteins bridge actin filaments to form bundles and networks

Figure 18-5


18.1 Cortical actin networks are connected to the plasma membrane: erythrocytes

Figure 18-7


18.1 During blood clotting, platelets change shape due to changes in the actin cytoskeleton

Figure 18-8


18.1 Cross-linkage of actin filament networks to the plasma membrane in various cells

Figure 18-9


18.1 Actin bundles support projecting fingers of membrane

Figure 18-10


18.2 Actin polymerization in vitro proceeds in three steps

Figure 18-11

Animação


18.2 Actin filaments grow faster at one end that at the other

Figure 18-13

Several toxins can disrupt the actin monomer-polymer equilibrium


18.2 Actin polymerization is regulated by proteins that bind G-actin

Figure 18-15a,b


18.2 Many movements are driven by actin polymerization

The acrosome reaction in echinoderm sperm

Figure 18-17


18.2 Movement of intracellular bacteria and viruses depends on actin polymerization

Figure 18-18


18.2 Actin polymerization at the leading edge of moving cells

Figure 18-19

Actin Dinamics in moving cells

Actin in Lamelipodia Movements


18.3 Myosin: the actin motor protein

All myosins have head, neck, and tail domains with distinct functions

Figure 18-20


18.3 Functions of the myosin tail domain

Figure 18-21


18.3 Myosin heads walk along actin filaments

Figure 18-22

animação


18.3 Myosin and kinesin share the Ras fold with certain signaling proteins

Figure 18-24


18.3 Conformational changes in the myosin head couple ATP hydrolysis to movement

Figure 18-25

animação


18.4 Muscle: a specialized contractile machine

Figure 18-26


18.4 Skeletal muscle contains a regular array of actin and myosin

Figure 18-27


18.4 Capping proteins stabilize the ends of actin thin filaments in the sarcomere

Figure 18-28


18.4 Thick and thin filaments slide past one another during contraction

Figure 18-29


18.4 Titin and nebulin filaments organize the sarcomere

Figure 18-30


18.4 A rise in cytosolic Ca2+ triggers muscle contraction (part I)

Figure 18-31a


18.4 A rise in cytosolic Ca2+ triggers muscle contraction (part II)

Figure 18-31b


18.4 Tropomyosin and troponin regulate contraction in skeletal muscle

Figure 18-32


18.4 Ca2+-dependent mechanisms for regulating contraction in skeletal and smooth muscle

Figure 18-33


18.4 Myosin-dependent mechanisms also control contraction in some muscles

Figure 18-34


18.5 Actin and myosin II are arranged in contractile bundles that function in cell adhesion

Figure 18-35


18.5 Myosin II stiffens cortical membranes

Figure 18-36


18.5 Actin and myosin II have essential roles in cytokinesis

Figure 18-37


18.6 Controlled polymerization and rearrangements of actin filaments occur during keratinocyte movement

Figure 18-41

Video

Animação


18.6 A model of the molecular events at the leading edge of a moving cell

Figure 18-42


18.6 Myosin I and myosin II have important roles in cell migration

Figure 18-43


18.6 Changes in localization of cytosolic Ca2+ during cell location

Figure 18-45


Chapter 19

Cell Motility and Shape II: Microtubules and Intermediate Filaments


19.1 Heterodimeric tubulin subunits compose the wall of a microtubule

Figure 19-1


19.1 Heterodimeric tubulin subunits compose the wall of a microtubule

Figure 19-2


19.1 Arrangement of protofilaments in singlet, doublet, and triplet microtubules

Figure 19-3


19.1 Microtubules form a diverse array of both permanent and transient structures

Figure 19-4

Microtubule networks


19.1 Microtubules assemble from organizing centers

Figure 19-5


19.1 The -tubulin ring complex nucleates polymerization of tubulin subunits

Figure 19-8


19.2 The steps of microtubule assembly

Figure 19-11


19.2 The ends of growing and shortening microtubules appear different

Figure 19-12


19.2 Dynamic instability is an intrinsic property of microtubules

Figure 19-13


19.2 Dynamic instability in vivo

Figure 19-14


19.2 The GTP cap model has been proposed to explain dynamic instability

Figure 19-15


19.2 Assembly MAPs co-localize with microtubules in vivo

Figure 19-17

Microtubules MAP4

MAP=Microtubule associated proteins


19.3 Different proteins are transported at different rates along axons

Figure 19-19


19.3 Fast axonal transport occurs along microtubules

Figure 19-20


19.3 Intracellular vesicles and some organelles travel along microtubules

Figure 19-22

ER

Microtubules


19.3 The structure of the kinesin microtubule motor protein

Figure 19-23


19.3 Kinesin is a (+) end-directed motor

Figure 19-24


19.3 Microtubule motors: kinesins and dyneins


19.3 Dynein-associated MBPs tether cargo to microtubules

Figure 19-25


19.3 Multiple motor proteins are associated with membrane vesicles

Figure 19-26


19.4 Cilia and flagella: structure and movement

Figure 19-27


19.4 All eukaryotic cilia and flagella contain bundles of doublet microtubules

Figure 19-28


19.4 Axonemes are connected to basal bodies

Figure 19-29


19.4 Ciliary and flagellar beating are produced by controlled sliding of outer doublet microtubules

Figure 19-30


19.4 Dynein arms generate the sliding forces in axonemes

Figure 19-31


19.4 Axonemal dyneins are multiheaded motor proteins

Figure 19-32


19.5 The stages of mitosis and cytokinesis in an animal cell

Figure 19-34Movimento dos cromossomas


19.6 Functions and structure of intermediate filaments distinguish them from other cytoskeletal fibers

Figure 19-50


19.6 All IF proteins have a conserved core domain and are organized similarly into filaments

Figure 19-51


19.6 A purified neurofilament

Figure 19-52


19.6 Intermediate filaments are dynamic polymers in the cell

Figure 19-53


19.6 Various proteins cross-link intermediate filaments and connect them to other cell structures

Figure 19-54


19.6 Intermediate filaments are anchored in cell junctions

Figure 19-56


19.6 Desmin and associated proteins stabilize sarcomeres in muscle

Figure 19-57

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Copyright (c) by W. H. Freeman and Company Chapter 18 Cell Motility and Shape I: Microfilaments