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Dynamique des Microtubules

Les microtubules sont des routes intracellulaires structurelles et fonctionnelles hautement dynamiques. Le terme cytosquelette évoque l'image d'une structure rigide, immuable et permanente. En réalité, le cytosquelette est un réseau interconnecté fortement dynamique constitué de trois différents composants principaux : les microtubules (dimères de tubuline), les microfilaments (actine polymérisée) et les filaments intermédiaires. Les microtubules sont les plus grands composants du cytosquelette. Ils jouent un rôle important dans pratiquement tous les processus cellulaires. Ils maintiennent la stabilité structurelle et la forme d'une cellule autrement amorphe. Ce sont les composants principaux dans un réseau "routier" intracellulaire par lequel toutes sortes de cargaisons cellulaires peuvent être transportées à l'aide d'un réseau actif de protéines motrices moléculaires. Pendant la mitose, la contraction du microtubule, concentrée sur un ou deux fuseaux mitotiques, fournit la force nécessaire à la division des chromosomes.

La nature constamment changeante du micro-environnement cellulaire rend nécessaire l'adaptabilité, particulièrement au cours du développement. Les microtubules et d'autres composants cytosquelettiques facilitent cette adaptabilité en raison de leur structure polymère. L'unité fondamentale du microtubule est un dimère de tubuline, composé d'une sous-unité tubuline alpha, et d'une sous-unité tubuline bêta correspondante. Ces dimères polymérisent pour former une structure tubulaire creuse de 24nm de large environ. L'état naturel non modifié de la tubuline est celui d'un flux constant, avec un taux presque égal de polymérisation et de dépolymérisation.

Plusieurs familles GTPase communes comme Rac et Rho favorisent indirectement l'assemblage du microtubule en facilitant l'échange GDP/GTP sur les dimères de tubuline. D'autres stabilisateurs de microtubule utilisent une approche plus directe. Les protéines associées au microtubule (MAPs) comme MAP1, MAP2, MAP4 ou MAPtau se lient aux microtubules polymérisés, stabilisent la forme polymérisée, favorisant l'assemblage et la croissance du microtubule. La plupart des MAPs sont activés par phosphorylation, et les MAPK (map kinase) ajoutent un niveau additionnel de contrôle au processus d'assemblage du microtubule. Réciproquement, les cellules ont différentes manières de réguler le désassemblage des microtubules. Les méthodes directes pour favoriser le désassemblage utilisent des composants comme la stathmine qui lie les dimères de tubuline alpha/bêta et les empêche de polymériser. Les enzymes coupant le microtubule comme la katanine, peuvent casser les microtubules au milieu de leur structure, alors que les membres de la famille de la kinésine I comme la KIF2 cheminent le long des microtubules et favorisent leur « effilochage » et leur dépolymérisation.

Microtubule-associated proteins

CLASP1 (Cytoplasmic Linker Associated Protein 1):

CLASPs, such as CLASP1, are nonmotor microtubule-associated proteins that interact with CLIPs (e.g., CLIP170\; MIM 179838). CLASP1 is involved in the regulation of microtubule dynamics at the kinetochore and throughout the spindle (Maiato et al., 2003 [PubMed 12837247]).[supplied by OMIM, Mar 2008].   More...

MAPT (Microtubule-Associated Protein tau):

This gene encodes the microtubule-associated protein tau (MAPT) whose transcript undergoes complex, regulated alternative splicing, giving rise to several mRNA species. MAPT transcripts are differentially expressed in the nervous system, depending on stage of neuronal maturation and neuron type. MAPT gene mutations have been associated with several neurodegenerative disorders such as...   More...
Antigène dans cette catégorie:
CLIP1 (CAP-GLY Domain Containing Linker Protein 1): CLIP1 anticorps CLIP1 ELISA Kits  
CLIP2 (CAP-GLY Domain Containing Linker Protein 2): CLIP2 anticorps CLIP2 ELISA Kits CLIP2 Proteins
CLASP2 (Cytoplasmic Linker Associated Protein 2): CLASP2 anticorps CLASP2 ELISA Kits CLASP2 Proteins
MAP1A (Microtubule-Associated Protein 1A): MAP1A anticorps MAP1A ELISA Kits MAP1A Proteins
MAP1B (Microtubule-Associated Protein 1B): MAP1B anticorps MAP1B ELISA Kits MAP1B Proteins
MAP4 (Microtubule-Associated Protein 4): MAP4 anticorps MAP4 ELISA Kits MAP4 Proteins

Tubulins

Tuba1a - TUBA1A

Tubulin is the major constituent of microtubules. It binds two moles of GTP, one at an exchangeable site on the beta chain and one at a non-exchangeable site on the alpha-chain.   More...

TUBB (Tubulin, beta):

beta 5-tubulin\; polymerizes to form microtubules\; member of a family of structural proteins [RGD, Feb 2006].   More...

TUBA4A (Tubulin, alpha 4a):

Microtubules of the eukaryotic cytoskeleton perform essential and diverse functions and are composed of a heterodimer of alpha and beta tubulin. The genes encoding these microtubule constituents are part of the tubulin superfamily, which is composed of six distinct families. Genes from the alpha, beta and gamma tubulin families are found in all eukaryotes. The alpha and beta tubulins represent...   More...

TUBE1 (Tubulin, epsilon 1):

This gene encodes a member of the tubulin superfamily. This protein localizes to the centriolar sub-distal appendages that are associated with the older of the two centrioles after centrosome duplication. This protein plays a central role in organization of the microtubules during centriole duplication. A pseudogene of this gene is found on chromosome 5.[provided by RefSeq, Jan 2009].   More...
Antigène dans cette catégorie:
TUBA1 - alpha Tubulin: TUBA1 anticorps    
LOC732582 - Tubulin A: LOC732582 anticorps    
TUBA1B (Tubulin, alpha 1B): TUBA1B anticorps TUBA1B ELISA Kits TUBA1B Proteins
TUBA1C (Tubulin, alpha 1c): TUBA1C anticorps TUBA1C ELISA Kits TUBA1C Proteins
TUBA3E (Tubulin, alpha 3e): TUBA3E anticorps   TUBA3E Proteins
TUBA8 (Tubulin, alpha 8): TUBA8 anticorps TUBA8 ELISA Kits TUBA8 Proteins
TUBA3C (Tubulin, Alpha, 3C): TUBA3C anticorps TUBA3C ELISA Kits TUBA3C Proteins
TUBB1 (Tubulin, beta 1): TUBB1 anticorps TUBB1 ELISA Kits TUBB1 Proteins
TUBB2A (Tubulin, beta 2A): TUBB2A anticorps TUBB2A ELISA Kits TUBB2A Proteins
TUBB2B (Tubulin, beta 2B): TUBB2B anticorps TUBB2B ELISA Kits TUBB2B Proteins
TUBb6 (Tubulin, beta 6): TUBb6 anticorps TUBb6 ELISA Kits TUBb6 Proteins
TUBB2C (Tubulin, Beta, 2C): TUBB2C anticorps TUBB2C ELISA Kits TUBB2C Proteins
TUBB3 (Tubulin, Beta, 3): TUBB3 anticorps TUBB3 ELISA Kits TUBB3 Proteins
TUBB5 (Tubulin, Beta, 5): TUBB5 anticorps TUBB5 ELISA Kits TUBB5 Proteins
TUBD1 (Tubulin, delta 1): TUBD1 anticorps TUBD1 ELISA Kits TUBD1 Proteins
TUBG1 (Tubulin, gamma 1): TUBG1 anticorps TUBG1 ELISA Kits TUBG1 Proteins
TUBG2 (Tubulin, gamma 2): TUBG2 anticorps TUBG2 ELISA Kits TUBG2 Proteins

Stabilization assembly

CLIP1 (CAP-GLY Domain Containing Linker Protein 1):

The protein encoded by this gene links endocytic vesicles to microtubules. This gene is highly expressed in Reed-Sternberg cells of Hodgkin disease. Several transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Oct 2011].   More...

CDC42 (Cell Division Cycle 42 (GTP Binding Protein, 25kDa)):

The protein encoded by this gene is a small GTPase of the Rho-subfamily, which regulates signaling pathways that control diverse cellular functions including cell morphology, migration, endocytosis and cell cycle progression. This protein is highly similar to Saccharomyces cerevisiae Cdc 42, and is able to complement the yeast cdc42-1 mutant. The product of oncogene Dbl was reported to...   More...

CLASP1 (Cytoplasmic Linker Associated Protein 1):

CLASPs, such as CLASP1, are nonmotor microtubule-associated proteins that interact with CLIPs (e.g., CLIP170\; MIM 179838). CLASP1 is involved in the regulation of microtubule dynamics at the kinetochore and throughout the spindle (Maiato et al., 2003 [PubMed 12837247]).[supplied by OMIM, Mar 2008].   More...
Antigène dans cette catégorie:
CLIP2 (CAP-GLY Domain Containing Linker Protein 2): CLIP2 anticorps CLIP2 ELISA Kits CLIP2 Proteins
CLASP2 (Cytoplasmic Linker Associated Protein 2): CLASP2 anticorps CLASP2 ELISA Kits CLASP2 Proteins
MAP1A (Microtubule-Associated Protein 1A): MAP1A anticorps MAP1A ELISA Kits MAP1A Proteins
MAP1B (Microtubule-Associated Protein 1B): MAP1B anticorps MAP1B ELISA Kits MAP1B Proteins
MAP4 (Microtubule-Associated Protein 4): MAP4 anticorps MAP4 ELISA Kits MAP4 Proteins
MAPT (Microtubule-Associated Protein tau): MAPT anticorps MAPT ELISA Kits MAPT Proteins
RHOA (Ras Homolog Gene Family, Member A): RHOA anticorps RHOA ELISA Kits RHOA Proteins
ROCK1 (rho-Associated, Coiled-Coil Containing Protein Kinase 1): ROCK1 anticorps ROCK1 ELISA Kits ROCK1 Proteins
ROCK2 (rho-Associated, Coiled-Coil Containing Protein Kinase 2): ROCK2 anticorps ROCK2 ELISA Kits ROCK2 Proteins

Destabilization assembly

FIGNL1 (Fidgetin-Like 1):

May regulate osteoblast proliferation and differentiation (By similarity).   More...

KIF2C (Kinesin Family Member 2C):

The protein encoded by this gene is a member of kinesin-like protein family. Proteins of this family are microtubule-dependent molecular motors that transport organelles within cells and move chromosomes during cell division. This protein is important for anaphase chromosome segregation and may be required to coordinate the onset of sister centromere separation. [provided by RefSeq, Jul 2008].   More...

vps4b - VPS4B

The protein encoded by this gene is a member of the AAA protein family (ATPases associated with diverse cellular activities), and is the homolog of the yeast Vps4 protein. In humans, two paralogs of the yeast protein have been identified. The former share a high degree of aa sequence similarity with each other, and also with yeast Vps4 and mouse Skd1 proteins. Mouse Skd1 (suppressor of K+...   More...
Antigène dans cette catégorie:
EML2 (Echinoderm Microtubule Associated Protein Like 2): EML2 anticorps EML2 ELISA Kits EML2 Proteins
KATNA1 (Katanin P60 (ATPase Containing) Subunit A 1): KATNA1 anticorps KATNA1 ELISA Kits KATNA1 Proteins
KATNB1 (Katanin P80 (WD Repeat Containing) Subunit B 1): KATNB1 anticorps KATNB1 ELISA Kits KATNB1 Proteins
KIF2B (Kinesin Family Member 2B): KIF2B anticorps KIF2B ELISA Kits KIF2B Proteins
KIF2A - Kinesin Heavy Chain Member 2A: KIF2A anticorps KIF2A ELISA Kits KIF2A Proteins
SPAST - Spastin: SPAST anticorps SPAST ELISA Kits SPAST Proteins
STMN1 - Stathmin 1: STMN1 anticorps STMN1 ELISA Kits STMN1 Proteins
VPS4A (Vacuolar Protein Sorting 4 Homolog A (S. Cerevisiae)): VPS4A anticorps VPS4A ELISA Kits VPS4A Proteins