background:
Tubulin family members are globular proteins important in the assembly of microtubules. Microtubules are structural components that play important roles in mitosis, cytokinesis and vesicle transport. TPPP (Tubulin polymerization-promoting protein), also known as p24 and p25, is a widely expressed 219 amino acid protein found in the perinuclear region of the cytoplasm. TPPP may form dimers and functions in polymerizing tubulin into double-walled tubules, polymorphic aggregates, or stabilized blocks. TPPP overexpression prevents formation of the mitotic spindle assembly and breakdown of the nuclear envelope. TPPP is phosphorylated by TPK II and is encoded by a gene that maps to human chromosome 5, which contains 181 million base pairs and comprises nearly 6% of the human genome.
Function:
May play a role in the polymerization of tubulin into microtubules, microtubule bundling and the stabilization of existing microtubules, thus maintaining the integrity of the microtubule network. May play a role in mitotic spindle assembly and nuclear envelope breakdown.
Subunit:
Homodimer. Binds tubulin; binding is inhibited by GTP (By similarity). Interacts with GSK3 (By similarity). Interacts with MAPK1 (By similarity). Interacts with GAPDH; the interaction is direct (By similarity). Interacts with LIMK1 (via the PDZ domain); the interaction is direct.
Subcellular Location:
Cytoplasm. Cytoplasm, cytoskeleton. Nucleus. Note=Localizes to glial Lewy bodies in the brains of individuals with synucleinopathies.
Tissue Specificity:
Widely expressed.
Post-translational modifications:
Poor substrate for GSK3 (By similarity). Phosphorylated by LIMK1 on serine residues. Phosphorylation may alter the tubulin polymerization activity.
Similarity:
Belongs to the TPPP family.
Database links:
UniProtKB/Swiss-Prot: O94811.1
Important Note:
This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications.
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