What is alpha tubulin?
Tubulins are the microtubule building block and exist as globular dimeric proteins of alpha/beta chains. There are five distinct forms: alpha, beta, gamma, delta, and epsilon tubulin.
How many amino acids are in alpha tubulin?
450 residues
The amino acid sequence of alpha-tubulin from porcine brain was determined by automated and manual Edman degradation of eight sets of overlapping peptides. It comprises 450 residues plus a COOH-terminal tyrosine that is present only in 15% of the material.
Does tubulin have a signal sequence?
None of the canonical nuclear localization signals (NLS) is detectable in tubulin sequences7,17. It is unlikely that tubulin enters the nucleus passively, since the tubulin heterodimer has a molecular weight of 110 kDa, extended to 138 kDa by the GFP tag, which is far above the size exclusion of nuclear pores.
Which molecule is associated with alpha-tubulin?
Tubulin in molecular biology can refer either to the tubulin protein superfamily of globular proteins, or one of the member proteins of that superfamily. α- and β-tubulins polymerize into microtubules, a major component of the eukaryotic cytoskeleton.
What do alpha-tubulin do?
Abstract. α- and β-tubulins polymerize to form polarized filaments called microtubules, which are critical for a variety of cellular activities, such as cell division, morphology, and intracellular transport.
What amino acids make up tubulin?
Abstract. The amino acid sequence of alpha-tubulin from porcine brain was determined by automated and manual Edman degradation of eight sets of overlapping peptides. It comprises 450 residues plus a COOH-terminal tyrosine that is present only in 15% of the material.
What is the molecular weight of alpha-tubulin?
50 kDa
Microtubules of the eukaryotic cytoskeleton perform essential and diverse functions and are composed of a heterodimer of alpha and beta tubulins. Alpha and beta tubulin dimers are assembled to 13 protofilaments that form a microtubule of 22 nm diameter with a theoretical molecular weight of 50 kDa.
What is the function of alpha-tubulin?
This contributes to locking the tubulin (beta tubulin) in the structure into a GDP-bound state. On the other hand, this tubulin forms a GTP cap that prevents the depolymerization of the microtubule given that it is exposed to solvent.
What phase is tubulin protein synthesis?
G2 phase
Synthesis occurred almost exclusively in the G2 phase of the cloned aneuploid V79 line, whereas in the diploid Don line, considerable microtubule protein was synthesized in mid S phase as well as G2.
Is alpha tubulin in the nucleus?
Microtubules are cylindrical organelles that play critical roles in cell division. Their subunit protein, tubulin, is a target for various antitumor drugs. Tubulin exists as various forms, known as isotypes. In most normal cells, tubulin occurs only in the cytosol and not in the nucleus.
What regulates microtubule assembly?
Centrosomes, in contrast, facilitate spindle assembly by providing sites for microtubule nucleation and organization. Centrosomes also help to concentrate various spindle assembly factors at the spindle poles during mitosis.