3.6.5.6	evolution	tubulin comes as a heterodimer of alpha and beta forms While there is only 45% amino-acid sequence similarity between alpha and beta tubulin isoforms, the three-dimensional structures of the monomers are very similar, each consisting of three domains of similar length and secondary structure composition: the N-terminal, the middle, and the C-terminal domain. Both alpha and beta bind GTP	756202	
3.6.5.6	malfunction	enhancement of tubulin polymerization by Cl--induced blockade of intrinsic GTPase	733253	
3.6.5.6	malfunction	in FtsZ mutants with severely reduced treadmilling, the spatial distribution of septal synthesis and the molecular composition and ultrastructure of the septal cell wall are substantially altered. Z-ring dynamics are significantly reduced in mutants with lower GTPase activity. In addition, the subunit exchange rate constants (kex) of these mutants decreases with kcat in a manner consistent with coupling to GTP hydrolysis. FtsZ GTPase mutants change the spatial distribution pattern but not the rate of septal PG synthesis	-, 758464	
3.6.5.6	malfunction	reduced levels of gamma-tubulin or impairment of its GTPase domain disrupts the mitochondrial network and alters both their respiratory capacity and the expression of mitochondrial-related genes. By contrast, reduced mitochondrial number or increased protein levels of gamma-tubulin DNA-binding domain enhance the association of gamma-tubulin with mitochondria. Increased mitochondria protein transport and low cellular mitochondria content affect the gamma-tubulin meshwork. Sg-mediated knockdown of gamma-tubulin affects the activity of the mitochondria, but not the structure of the endoplasmic reticulum	756504	
3.6.5.6	malfunction	the buried mutation T238A in alphabeta-tubulin yields microtubules with dramatically reduced shrinking rate and catastrophe frequency, the mutation uncouples the tubulin conformational and GTPase cycles, revealing allosteric control of microtubule dynamics. The mutation causes these effects by suppressing a conformational change that normally occurs in response to GTP hydrolysis in the lattice, without detectably changing the conformation of unpolymerized alphabetab-tubulin. The mutation predominantly affects post-GTPase conformational and dynamic properties of microtubules, phenotype, overview	733717	
3.6.5.6	metabolism	gamma-tubulin forms a cellular meshwork of gamma-strings and gamma-tubules. While gamma-tubules are polar cytosolic filaments within the gamma-string meshwork, gamma-strings are detected in both the cytoplasm and the nucleus and are formed of non-polar protein threads that cross the double membrane of the nuclear envelope. The gamma-string meshwork forms a boundary around chromatin, which coordinates cytosolic and nuclear events during mitosis by assuring that a nuclear envelope forms around daughter chromosomes. The gamma-tubulin meshwork may be a dynamic network that contributes to cellular homeostasis	756504	
3.6.5.6	metabolism	microtubule dynamic instability depends on the GTPase activity of the polymerizing alphabeta-tubulin subunits, which cycle through at least three distinct conformations as they move into and out of microtubules. This conformational cycle contributes to microtubule growing, shrinking, and switching	733717	
3.6.5.6	metabolism	the enzyme is involved in the mechanisms underlying regulation of cell division in response to DNA damage	733983	
3.6.5.6	additional information	determination of Z-ring dynamics in live Escherichia coli strain BW25113 cells by using total internal reflection fluorescence (TIRF) microscopy to monitor the fluorescence of an FtsZ-GFP fusion protein. Mutants lacking one of the proteins that regulates the Z-ring (SlmA, SulA, MinC, ClpX, and ClpP) or stabilizes it (ZapA, ZapB, ZapC, ZapD, and MatP) also display wild-type Z-ring behavior. Thus, Z-ring dynamics are likely due to FtsZ's intrinsic polymerization properties, which are related to its GTPase activity. Z-ring dynamics were significantly reduced in mutants with lower GTPase activity	-, 758464	
3.6.5.6	physiological function	a part of stimulatory effects of Cl- on in vitro tubulin polymerization is mediated via an inhibitory effect on GTPase activity of tubulin, although Cl- also regulates in vitro tubulin polymerization by factors other than an inhibitory effect on GTPase activity	733253	
3.6.5.6	physiological function	an important regulator of microtubule dynamics during cell division is the protein gamma-tubulin. gamma-Tubulin expression and its GTPase domain are necessary for the organization of mitochondria in tubular structures. In the cell, gamma-tubulin establishes a cellular network of threads named the gamma-string meshwork. gamma-Strings have the ability to connect the cytoplasm and the mitochondrial DNA together. gamma-Tubulin has a role in the maintenance of the mitochondrial network and functions. The endoplasmic reticulum is not affected by gamma-tubulin. gamma-Tubulin provides a cytoskeletal element that gives form to the mitochondrial network. gamma-Tubulin regulates the expression of mitochondrial genes, overview of upregulated mitochondria-related genes. It affects the replication of mitochondrial DNA	756504	
3.6.5.6	physiological function	FtsZDr, a tubulin homologue in radioresistant bacterium Deinococcus radiodurans, is characterized as a GTPase exhibiting polymerization/depolymerization dynamics in vitro and FtsZ ring formation in vivo	733983	
3.6.5.6	physiological function	microtubules are amazing filaments made of GTPase enzymes that store energy used for their own selfdestruction to cause a stochastically driven dynamic called dynamic instability. Dynamic instability can be reproduced in vitro with purified tubulin, but the dynamics do not mimic that observed in cells. This is because stabilizers, e.g. paclitaxel, and destabilizers, e.g. Ca2+, act to alter microtubule dynamics. Another class of destabilizers consists of the microtubule-severing enzymes from the ATPases associated with various cellular activities (AAA+) family of ATP-enzymes. GTP-driven microtubule dynamics are coupled to ATP-driven destabilization by severing enzymes. The GTP enzyme that polymerizes into the microtubules is called tubulin, which comes as a heterodimer of alpha and beta forms. Tubulin controls microtubule dynamics, analysis of GTP hydrolysis on reconstructed microtubules, mechanism, overview	756202	
3.6.5.6	physiological function	the enzyme activity is esentially coupled to the alphabeta-tubulin conformational cycle that contributes to microtubule dynamics, overview. alphabeta-Tubulin conformational changes occur as a consequence of GTP hydrolysis deeper in the microtubule lattice	733717	
3.6.5.6	physiological function	the tubulin homologue FtsZ is the central component of the cell division machinery in nearly all walled bacterial species. During division, FtsZ polymerizes on the cytoplasmic face of the inner membrane to form a ring-like structure, the Z-ring, and recruits more than 30 proteins to the division site. Many of these proteins are involved in septal synthesis of the peptidoglycan (PG) cell wall. The guanosine triphosphatase (GTPase) activity of FtsZ is highly conserved, and the binding and hydrolysis of GTP underlie the dynamic assembly and disassembly of FtsZ. Exceptionally, in Escherichia coli the GTPase activity of FtsZ appears nonessential for cell division and does not dictate the cell constriction rate. In Escherichia coli cells, FtsZ exhibits dynamic treadmilling predominantly determined by its guanosine triphosphatase activity. The treadmilling dynamics direct the processive movement of the septal cell wall synthesis machinery but do not limit the rate of septal synthesis. FtsZ treadmilling provides a mechanism for achieving uniform septal cell wall synthesis to enable correct polar morphology	-, 758464