TUBB4B

TUBB4B (Tubulin Beta 4B Class IVb) is a Protein Coding gene. Diseases related to TUBB4B include Chondroid Chordoma. Among its related pathways are Development Slit-Robo signaling and Organelle biogenesis and maintenance. Gene Ontology (GO) annotations related to TUBB4B include GTP binding and unfolded protein binding. An important paralog of TUBB4B is TUBB4A.

Full Name

tubulin, beta 4B class IVb

Function

Tubulin is the major constituent of microtubules, a cylinder consisting of laterally associated linear protofilaments composed of alpha- and beta-tubulin heterodimers. Microtubules grow by the addition of GTP-tubulin dimers to the microtubule end, where a stabilizing cap forms. Below the cap, tubulin dimers are in GDP-bound state, owing to GTPase activity of alpha-tubulin.

Biological Process

Biological Process microtubule cytoskeleton organization Source:GO_Central1 Publication
Biological Process mitotic cell cycle Source:GO_Central1 Publication
Biological Process natural killer cell mediated cytotoxicity Source:UniProtKB1 Publication

Cellular Location

Cytoplasm, cytoskeleton

Involvement in disease

Leber congenital amaurosis with early-onset deafness (LCAEOD):
An autosomal dominant disease characterized by severe retinal degeneration and sensorineural hearing loss. Symptoms occur within the first decade of life. Onset at birth is observed in some patients.

PTM

Some glutamate residues at the C-terminus are polyglutamylated, resulting in polyglutamate chains on the gamma-carboxyl group (PubMed:26875866).
Polyglutamylation plays a key role in microtubule severing by spastin (SPAST). SPAST preferentially recognizes and acts on microtubules decorated with short polyglutamate tails: severing activity by SPAST increases as the number of glutamates per tubulin rises from one to eight, but decreases beyond this glutamylation threshold (PubMed:26875866).
Glutamylation is also involved in cilia motility (By similarity).
Some glutamate residues at the C-terminus are monoglycylated but not polyglycylated due to the absence of functional TTLL10 in human. Monoglycylation is mainly limited to tubulin incorporated into cilia and flagella axonemes, which is required for their stability and maintenance. Flagella glycylation controls sperm motility. Both polyglutamylation and monoglycylation can coexist on the same protein on adjacent residues, and lowering glycylation levels increases polyglutamylation, and reciprocally.
Phosphorylated on Ser-172 by CDK1 during the cell cycle, from metaphase to telophase, but not in interphase. This phosphorylation inhibits tubulin incorporation into microtubules.