Tel:
+1 877 302 8632
Fax:
+1 888 205 9894 (Toll-free)
E-Mail:
orders@anticorps-enligne.fr

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...

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

CLIP2 (CAP-GLY Domain Containing Linker Protein 2):

Tubulins

Tuba1a - TUBA1A

Microtubules of the eukaryotic cytoskeleton perform essential and diverse functions and are composed of a heterodimer of alpha and beta tubulins. The genes encoding these microtubule constituents belong to 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...

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...

LOC732582 - Tubulin A:

TUBb6 (Tubulin, beta 6):

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...

CLIP2 (CAP-GLY Domain Containing Linker Protein 2):

ROCK1 (rho-Associated, Coiled-Coil Containing Protein Kinase 1):

ROCK2 (rho-Associated, Coiled-Coil Containing Protein Kinase 2):

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...

EML2 (Echinoderm Microtubule Associated Protein Like 2):

KATNA1 (Katanin P60 (ATPase Containing) Subunit A 1):

KIF2B (Kinesin Family Member 2B):

VPS4A (Vacuolar Protein Sorting 4 Homolog A (S. Cerevisiae)):

Vous êtes ici: