Microtubule mutants

1985 ◽  
Vol 63 (6) ◽  
pp. 479-488 ◽  
Author(s):  
Berl R. Oakley
Keyword(s):  
Force Production ◽  
Structure And Function ◽  
Mechanisms Of Resistance ◽  
Cellular Event ◽  
Cellular Events ◽  
And Function ◽  
Microtubule Function ◽  
Microtubule Structure ◽  
Β Tubulin

Genetics has become an important tool for studying microtubule structure and function. Mutations in genes that encode microtubule proteins have been isolated in several, evolutionarily diverse organisms. These mutations have been, and will increasingly be, of great value in determining which cellular events are microtubule mediated, in determining which genes encode the microtubule proteins involved in a particular cellular event, and in determining the mechanisms of resistance to anti-microtubule drugs. These mutants also have great potential, which is just beginning to be realized, for identifying proteins other than α- and β-tubulin that are essential to microtubule function and for determining the mechanisms of microtubule-based force production in mitosis and organellar movement.

scholarly journals Structural basis of motility in the microtubular axostyle: implications for cytoplasmic microtubule structure and function.

1980 ◽  
Vol 87 (2) ◽  
pp. 404-414 ◽  
Author(s):  
D T Woodrum ◽  
R W Linck
Keyword(s):  
Structural Analysis ◽  
Protein S ◽  
Structure And Function ◽  
Structural Basis ◽  
Cytoplasmic Microtubule ◽  
Left Handed ◽  
And Function ◽  
Specific Array ◽  
Microtubule Function ◽  
Microtubule Structure

The gross morphology of the protozoan microtubule axostyle of Saccinobaculus ambloaxostylus can now be described in macromolecular detail. The left-handed coil of the axostyle is seen to be dependent upon the asymmetry inherent in the constituent microtubules as expressed by the specific array of linkages between microtubules and by a possible tendency for microtubules to coil into left-handed helices. The laminated sheets of microtubules are not aligned parallel to the long axis of the organelle, but become increasingly tilted off-axis as one descends through the sheets of microtubules from the convex to the concave surface of the axostyle. Fine-structural analysis of the axostyle indicates similarities of the linkages to dynein. The potential loci of the force-generating protein(s) are discussed as well as implications of the axostyle's structure on general microtubule function.

scholarly journals Fundamental Characteristics of AAA+ Protein Family Structure and Function

Archaea ◽  
2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Justin M. Miller ◽  
Eric J. Enemark
Keyword(s):  
Atp Hydrolysis ◽  
Molecular Machines ◽  
Ring Structure ◽  
Structure And Function ◽  
Central Channel ◽  
Aaa Atpase ◽  
Cellular Events ◽  
Critical Components ◽  
And Function ◽  
Aaa Protein

Many complex cellular events depend on multiprotein complexes known as molecular machines to efficiently couple the energy derived from adenosine triphosphate hydrolysis to the generation of mechanical force. Members of the AAA+ ATPase superfamily (ATPases Associated with various cellular Activities) are critical components of many molecular machines. AAA+ proteins are defined by conserved modules that precisely position the active site elements of two adjacent subunits to catalyze ATP hydrolysis. In many cases, AAA+ proteins form a ring structure that translocates a polymeric substrate through the central channel using specialized loops that project into the central channel. We discuss the major features of AAA+ protein structure and function with an emphasis on pivotal aspects elucidated with archaeal proteins.

scholarly journals Cytoskeleton and Adhesion in Myogenesis

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
Manoel Luís Costa
Keyword(s):  
Skeletal Muscle ◽  
Extracellular Matrix ◽  
Smooth Muscle ◽  
Muscle Function ◽  
Force Production ◽  
Structure And Function ◽  
Cytoskeletal Proteins ◽  
Skeletal Muscle Differentiation ◽  
And Function ◽  
Structural Adaptations

The function of muscle is to contract, which means to exert force on a substrate. The adaptations required for skeletal muscle differentiation, from a prototypic cell, involve specialization of housekeeping cytoskeletal contracting and supporting systems into crystalline arrays of proteins. Here I discuss the changes that all three cytoskeletal systems (microfilaments, intermediate filaments, and microtubules) undergo through myogenesis. I also discuss their interaction, through the membrane, to extracellular matrix and to other cells, where force will be exerted during contraction. The three cytoskeletal systems are necessary for the muscle cell and must exert complementary roles in the cell. Muscle is a responsive system, where structure and function are integrated: the structural adaptations it undergoes depend on force production. In this way, the muscle cytoskeleton is a portrait of its physiology. I review the cytoskeletal proteins and structures involved in muscle function and focus particularly on their role in myogenesis, the process by which this incredible muscle machine is made. Although the focus is on skeletal muscle, some of the discussion is applicable to cardiac and smooth muscle.

scholarly journals A lineage-restricted and divergent β-tubulin isoform is essential for the biogenesis, structure and function of blood platelets

2001 ◽  
Vol 11 (8) ◽  
pp. 579-586 ◽  
Author(s):  
Heinz D Schwer ◽  
Patrick Lecine ◽  
Sanjay Tiwari ◽  
Joseph E Italiano ◽  
John H Hartwig ◽  
...  
Keyword(s):  
Blood Platelets ◽  
Structure And Function ◽  
And Function ◽  
Β Tubulin

Regulation of Golgi structure and function by ARF-like protein 1 (Arl1)

2001 ◽  
Vol 114 (24) ◽  
pp. 4543-4555 ◽  
Author(s):  
Lei Lu ◽  
Heinz Horstmann ◽  
Cheepeng Ng ◽  
Wanjin Hong
Keyword(s):  
Golgi Apparatus ◽  
Secretory Pathway ◽  
Small Gtpases ◽  
Structure And Function ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Intact Cells ◽  
Cellular Events ◽  
Golgi Structure ◽  
And Function

Arl1 is a member of the ARF-like protein (Arl) subfamily of small GTPases. Nothing is known about the function of Arl1 except for the fact that it is essential for normal development in Drosophila and that it is associated with the Golgi apparatus. In this study, we first demonstrate that Arl1 is enriched at the trans side of the Golgi, marked by AP-1. Association of Arl1 with the Golgi is saturable in intact cells and depends on N-terminal myristoylation. Over-expression of Arl1(T31N), which is expected to be restricted to the GDP-bound form and thus function as a dominant-negative mutant, causes the disappearance of the Golgi apparatus (marked by Golgi SNARE GS28), suggesting that Arl1 is necessary for maintaining normal Golgi structure. Overexpression of Arl1(Q71L), a mutant restricted primarily to the activated GTP-bound form, causes an expansion of the Golgi apparatus with massive and stable Golgi association of COPI and AP-1 coats. Interestingly, Golgi ARFs also become stably associated with the expanded Golgi. Transport of the envelope protein of vesicular stomatitis virus (VSV-G) along the secretory pathway is arrested at the expanded Golgi upon expression of Arl1(Q71L). The structure of stacked cisternae of the Golgi is disrupted in cells expressing Arl1(Q71L), resulting in the transformation of the Golgi into an extensive vesicule-tubule network. In addition, the GTP form of Arl1 interacts with arfaptin-2/POR1 but not GGA1, both of which interact with GTP-restricted ARF1, suggesting that Arl1 and ARF1 share some common effectors in regulating cellular events. On the basis of these observations, we propose that one of the mechanisms for the cell to regulate the structure and function of the Golgi apparatus is through the action of Arl1.

Connective tissue and inflammation

2014 ◽  
Vol 155 (12) ◽  
pp. 453-460 ◽  
Author(s):  
Lajos Jakab
Keyword(s):  
Immune Response ◽  
Connective Tissue ◽  
Adaptive Immune Response ◽  
Sialic Acids ◽  
Structure And Function ◽  
Psychological State ◽  
Connective Tissues ◽  
Cellular Events ◽  
Inflammatory Processes ◽  
And Function

The author summarizes the structure of the connective tissues, the increasing motion of the constituents, which determine the role in establishing the structure and function of that. The structure and function of the connective tissue are related to each other in the resting as well as inflammatory states. It is emphasized that cellular events in the connective tissue are part of the defence of the organism, the localisation of the damage and, if possible, the maintenance of restitutio ad integrum. The organism responds to damage with inflammation, the non specific immune response, as well as specific, adaptive immunity. These processes are located in the connective tissue. Sterile and pathogenic inflammation are relatively similar processes, but inevitable differences are present, too. Sialic acids and glycoproteins containing sialic acids have important roles, and the role of Siglecs is also highlighted. Also, similarities and differences in damages caused by pathogens and sterile agents are briefly summarized. In addition, the roles of adhesion molecules linked to each other, and the whole event of inflammatory processes are presented. When considering practical consequences it is stressed that the structure (building up) of the organism and the defending function of inflammation both have fundamental importance. Inflammation has a crucial role in maintaining the integrity and the unimpaired somato-psychological state of the organism. Thus, inflammation serves as a tool of organism identical with the natural immune response, inseparably connected with the specific, adaptive immune response. The main events of the inflammatory processes take place in the connective tissue. Orv. Hetil., 2014, 155(12), 453–460.

scholarly journals Caenorhabditis elegans male sensory-motor neurons and dopaminergic support cells couple ejaculation and post-ejaculatory behaviors

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Brigitte LeBoeuf ◽  
Paola Correa ◽  
Changhoon Jee ◽  
L René García
Keyword(s):  
Motor Neurons ◽  
Structure And Function ◽  
Intrauterine Environment ◽  
C Elegans ◽  
Cellular Events ◽  
Sensory Motor ◽  
Circuit Structure ◽  
Circuit Components ◽  
And Function ◽  
Sperm Movement

The circuit structure and function underlying post-coital male behaviors remain poorly understood. Using mutant analysis, laser ablation, optogenetics, and Ca2+ imaging, we observed that following C. elegans male copulation, the duration of post-coital lethargy is coupled to cellular events involved in ejaculation. We show that the SPV and SPD spicule-associated sensory neurons and the spicule socket neuronal support cells function with intromission circuit components, including the cholinergic SPC and PCB and the glutamatergic PCA sensory-motor neurons, to coordinate sex muscle contractions with initiation and continuation of sperm movement. Our observations suggest that the SPV and SPD and their associated dopamine-containing socket cells sense the intrauterine environment through cellular endings exposed at the spicule tips and regulate both sperm release into the hermaphrodite and the recovery from post-coital lethargy.

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