Microtubules are highly-dynamic structural and functional intracellular highways. The term cytoskeleton conjures up an image of rigid, immutable, and permanent structure. In reality, the cytoskeleton is a highly dynamic interconnected network composed of three different principal components: microtubules (polymerized tubulin dimers), microfilaments (polymerized actin), and intermediate filaments. Microtubules are the largest cytoskeletal components. They play a role in nearly every cellular process. They give structural stability and form to an otherwise amorphous cell. They are the principal components in an interconnected intracellular “highway” by which all manner cellular cargo may be shuttled via a bustling network of molecular motor proteins. During mitosis, microtubule contraction, focused at one of two mitotic spindles, provides the force necessary to divide chromosomes.
The ever changing nature of the cellular microenvironment necessitates adaptability, particularly during development. Microtubules and other cytoskeletal components facilitate this adaptability by virtue of their polymeric structure. The fundamental unit of the microtubule is a tubulin dimer, composed of one alpha tubulin-subunit, and one corresponding beta-tubulin subunit. These dimers polymerize to form a hollow, tubular structure approximately 24nm wide. The natural state of unmodified tubulin is one of constant flux, with a nearly equal rate of polymerization and depolymerization. Several common GTPase families like Rac and Rho promote microtubule assembly indirectly by facilitating GDP/GTP exchange on regulatory members that effect assembly and disassembly of tubulin dimers. Other microtubule stabilizers take a more direct approach. Microtubule associated proteins like MAP1, MAP2, MAP4, or MAPtau bind polymerized microtubules stabilize the polymerized form, promoting assembly and microtubule growth. Most MAPs are activated by phosphorylation, and MAPK (map kinase) phosphorylation cascades add an additional layer of control to the process of microtubule assembly.
Conversely, cells have several different ways to regulate microtubule disassembly. Direct methods for promoting disassembly include components like Stathmin, which binds alpha/beta-tubulin dimers and prevents them from polymerizing. Microtubule severing enzymes like Katanin are able to break microtubules in the middle of their structure, while Kinesin I family members like KIF2 walk along microtubules and promote “fraying” and depolymerization.
CLIP1 (CAP-GLY Domain Containing Linker Protein 1): | CLIP1 antibodies | ||
CLIP2 (CAP-GLY Domain Containing Linker Protein 2): | CLIP2 antibodies | CLIP2 Proteins | |
CLASP2 (Cytoplasmic Linker Associated Protein 2): | CLASP2 antibodies | CLASP2 ELISA Kits | CLASP2 Proteins |
MAP1A (Microtubule-Associated Protein 1A): | MAP1A antibodies | MAP1A ELISA Kits | MAP1A Proteins |
MAP1B (Microtubule-Associated Protein 1B): | MAP1B antibodies | MAP1B ELISA Kits | MAP1B Proteins |
MAP4 (Microtubule-Associated Protein 4): | MAP4 antibodies | MAP4 ELISA Kits | MAP4 Proteins |
CLIP2 (CAP-GLY Domain Containing Linker Protein 2): | CLIP2 antibodies | CLIP2 Proteins | |
CLASP2 (Cytoplasmic Linker Associated Protein 2): | CLASP2 antibodies | CLASP2 ELISA Kits | CLASP2 Proteins |
MAP1A (Microtubule-Associated Protein 1A): | MAP1A antibodies | MAP1A ELISA Kits | MAP1A Proteins |
MAP1B (Microtubule-Associated Protein 1B): | MAP1B antibodies | MAP1B ELISA Kits | MAP1B Proteins |
MAP4 (Microtubule-Associated Protein 4): | MAP4 antibodies | MAP4 ELISA Kits | MAP4 Proteins |
MAPT (Microtubule-Associated Protein tau): | MAPT antibodies | MAPT ELISA Kits | MAPT Proteins |
RHOA (Ras Homolog Gene Family, Member A): | RHOA antibodies | RHOA ELISA Kits | RHOA Proteins |
ROCK1 (rho-Associated, Coiled-Coil Containing Protein Kinase 1): | ROCK1 antibodies | ROCK1 ELISA Kits | ROCK1 Proteins |
ROCK2 (rho-Associated, Coiled-Coil Containing Protein Kinase 2): | ROCK2 antibodies | ROCK2 ELISA Kits | ROCK2 Proteins |
EML2 (Echinoderm Microtubule Associated Protein Like 2): | EML2 antibodies | EML2 Proteins | |
KATNA1 (Katanin P60 (ATPase Containing) Subunit A 1): | KATNA1 antibodies | KATNA1 Proteins | |
KATNB1 (Katanin P80 (WD Repeat Containing) Subunit B 1): | KATNB1 antibodies | KATNB1 ELISA Kits | KATNB1 Proteins |
KIF2B (Kinesin Family Member 2B): | KIF2B antibodies | ||
KIF2A - Kinesin Heavy Chain Member 2A: | KIF2A antibodies | KIF2A ELISA Kits | KIF2A Proteins |
SPAST - Spastin: | SPAST antibodies | SPAST ELISA Kits | SPAST Proteins |
STMN1 - Stathmin 1: | STMN1 antibodies | STMN1 ELISA Kits | STMN1 Proteins |
VPS4A (Vacuolar Protein Sorting 4 Homolog A (S. Cerevisiae)): | VPS4A antibodies | VPS4A Proteins |