Motor proteins dynein

The six ATPases belong to the rather large family of AAA ATPases (for ATPases Associated with a variety of cellular Activities) whose eukaryotic members include the motor protein dynein, the membrane fusion factor NSF, and the chaperone... 

Fast anterograde transport can reach rates as high as 400 mm/day. It is dependent upon microtubules that provide a track along which the vesicles move. The movement is energy dependent and is mediated by a specific motor protein, kinesin. A similar process is responsible for fast retrograde transport. A second motor protein, dynein, is needed for movement in that direction. A third type of transport process is termed slow axoplasmic transport. It ranges from 0.2 to 5 mm/day and is responsible for the transport of cytoskeletal proteins, the neurofilaments, and microtubules, as well as an assortment of cytoplasmic proteins. 

PPIases are also associated with motor proteins the first PPIase domain of hFKBP52 (and to a lesser extent hCyp40) binds to the microtubule-associated motor protein dynein [21] and some authors propose that the amino acyl proline CTI plays an important part in the protein transconformation that directs relative molecular motion in contractile muscle fibers [22]. However, there is presently no evidence that PPIases are directly implicated in muscle diseases. 

FIP-2, also called NEMO-related protein, contains two leucine zipper domains. Overexpression of FIP-2 does not cause cell death, but can reverse the protective effect of 14.7K on cell death induced by overexpression of the TNFR intracellular domain or RIP (Li et al. 1998). FIP-1 is identical to RagA and belongs to the family of small GTPases (Li et al. 1997). It does not cause cell death but forms ternary complexes with 14.7K and TCTEL, a component of the microtubule motor protein dynein (Horwitz 2001). It will be interesting to see whether these interactions of 14.7K are also detectable during virus infection and whether they influence the TNF signal cascade. 

Certain proteins endow cells with unique capabilities for movement. Cell division, muscle contraction, and cell motility represent some of the ways in which cells execute motion. The contractile and motile proteins underlying these motions share a common property they are filamentous or polymerize to form filaments. Examples include actin and myosin, the filamentous proteins forming the contractile systems of cells, and tubulin, the major component of microtubules (the filaments involved in the mitotic spindle of cell division as well as in flagella and cilia). Another class of proteins involved in movement includes dynein and kinesin, so-called motor proteins that drive the movement of vesicles, granules, and organelles along microtubules serving as established cytoskeletal tracks. ... 

Motor proteins move along MTs in an ATP-dependent manner. Members of the superfamily of kinesin motors move only to the plus ends and dynein motors only to the minus ends. The respective motor domains are linked via adaptor proteins to their cargoes. The binding activity of the motors to MTs is regulated by kinases and phosphatases. When motors are immobilized at their cargo-binding area, they can move MTs. 

Dynein, kinesin, and myosin are motor proteins with ATPase activity that convert the chemical bond energy released by ATP hydrolysis into mechanical work. Each motor molecule reacts cyclically with a polymerized cytoskeletal filament in this chemomechanical transduction process. The motor protein first binds to the filament and then undergoes a conformational change that produces an increment of movement, known as the power stroke. The motor protein then releases its hold on the filament before reattaching at a new site to begin another cycle. Events in the mechanical cycle are believed to depend on intermediate steps in the ATPase cycle. Cytoplasmic dynein and kinesin walk (albeit in opposite... 

Even though dynein, kinesin, and myosin serve similar ATPase-dependent chemomechanical functions and have structural similarities, they do not appear to be related to each other in molecular terms. Their similarity lies in the overall shape of the molecule, which is composed of a pair of globular heads that bind microtubules and a fan-shaped tail piece (not present in myosin) that is suspected to carry the attachment site for membranous vesicles and other cytoplasmic components transported by MT. The cytoplasmic and axonemal dyneins are similar in structure (Hirokawa et al., 1989 Holzbaur and Vallee, 1994). Current studies on mutant phenotypes are likely to lead to a better understanding of the cellular roles of molecular motor proteins and their mechanisms of action (Endow and Titus, 1992). 

Dynein Motor protein mediating microtubule-based synaptic vesicle transport. May be involved in retrograde axonal transport to the cell body. 

With regard to microtubular ultrastructure, micro filaments (5-7 run in diameter) are composed of filamentous actin. The tubule-like structures are formed by a, P-tubulin heterodimers. The wall is composed of 13 parallel protofilaments. Various microtubule-associated proteins and motor proteins (kinesin and dynein) are bound to the wall. The microtubule is a polar structure, i.e., plus and minus ends. 

The midpiece contains the mitochondria which are wrapped around the proximal part of the flagellum. The beating of the flagellum, and hence the swimming of the sperm involves the motor protein known as dynein, which requires ATP hydrolysis. In some species, the diffusion of energy in the spermatozoa is increased by the presence of the creatine/phosphocreatine shuttle (Chapter 9) that is, phosphocreatine and creatine diffuse throughout the cytosol... 

Microtubules in the long axons of nerve cells function as "rails" for the "fast transport" of proteins and other materials from the cell body down the axons. In fact, microtubules appear to be present throughout the cytoplasm of virtually all eukaryotic cells (Fig. 7-32) and also in spirochetes.311 Motion in microtubular systems depends upon motor proteins such as kinesin, which moves bound materials toward what is known as the "negative" end of the microtubule,312 dyneins which move toward the positive end.310 These motor proteins are driven by the Gibbs energy of hydrolysis of ATP or GTP and in this respect, as well as in some structural details (Chapter 19), resemble the muscle protein myosin. Dynein is present in the arms of the microtubules of cilia (Fig. 1-8) whose motion results from the sliding of the microtubules driven by the action of this protein (Chapter 19). 

Gibbons, I. R. (1995). Dynein family of motor proteins Present status and future questions. Cell Motil. Cytoskel. 32, 136-144. 

The present volume covers Muscle and Molecular Motors . The first few chapters describe the ultrastructures of striated muscles and of various muscle filaments (myosin, actin, titin), they discuss the regulation of muscle contractile activity, and they explore the mechanism of force production and movement. The book then sets out to survey other kinds of motor systems microtubules and their interactions with both microtubule associated proteins (MAPs) and the motor proteins kinesin and dynein, the major sperm protein in nematodes, the rotary ATPases driven by or driving proton gradients, and the action of motor enzymes, polymerases, on nucleic acids. The aim throughout is to explore different molecular mechanisms of motor action in order to identify common themes. 

Microtubules are the intracellular tracks for two classes of motor proteins kinesins and dyneins. During the past few years, the motor domain structures of several kinesins from different organisms have been determined by X-ray crystallography. Compared with kinesins, dyneins are much larger proteins and attempts to crystallize them have failed so far. Structural information about these proteins comes mosdy from electron microscopy. In this chapter, we mainly focus on the crystal structures of kinesin motor domains. 

Vallee, R. B., Williams, J. C., Varma, D., and Barnhart, L. E. (2004). Dynein An ancient motor protein involved in multiple modes of transport./. Neurobiol. 58, 189-200. 

Two other projections adorn each peripheral microtubule they are called the outer arm and the inner arm. Biochemical analysis has shown that these projections contain a protein called dynein. Dynein is a member of a class of proteins called motor proteins, which function as tiny motors in the cell, powering mechanical motion. ... 

In a more technical vein, Miller excitedly announced that some components of IC biochemical systems I discuss have other roles in the cell, such as the ciliary proteins tubulin and dynein.11 But I myself pointed that out when I first wrote Darwin s Black Box ten years ago For example, in Chapter 3 I wrote that microtubules occur in many cells and are usually used as mere structural supports, like girders, to prop up cell shape.12 Furthermore, motor proteins also are involved in other cell functions, such as transporting cargo from one end of the cell to another. Nonetheless, I emphasized that such other roles don t help with the irreducible complexity of the cilium an evolutionary story for the cilium must envision a circuitous route, perhaps adapting parts that were originally used for other purposes to build a cilium. And I went on to show why indirect routes are quite implausible.13 Toothpicks do not... 

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