TPPP

TPPP (Tubulin Polymerization Promoting Protein) is a Protein Coding gene. Diseases related to TPPP include Lymphoid Interstitial Pneumonia and Dementia, Lewy Body. Among its related pathways are Glial Cell Differentiation and Sudden Infant Death Syndrome (SIDS) Susceptibility Pathways. Gene Ontology (GO) annotations related to TPPP include microtubule binding and tubulin binding. An important paralog of TPPP is TPPP3.

Full Name

Tubulin Polymerization Promoting Protein

Function

Regulator of microtubule dynamics that plays a key role in myelination by promoting elongation of the myelin sheath (PubMed:31522887).
Acts as a microtubule nucleation factor in oligodendrocytes: specifically localizes to the postsynaptic Golgi apparatus region, also named Golgi outpost, and promotes microtubule nucleation, an important step for elongation of the myelin sheath (PubMed:31522887, PubMed:33831707).
Required for both uniform polarized growth of distal microtubules as well as directing the branching of proximal processes (PubMed:31522887).
Shows magnesium-dependent GTPase activity; the role of the GTPase activity is unclear (PubMed:21995432, PubMed:21316364).
In addition to microtubule nucleation activity, also involved in microtubule bundling and stabilization of existing microtubules, thereby maintaining the integrity of the microtubule network (PubMed:17105200, PubMed:17693641, PubMed:18028908, PubMed:26289831).
Regulates microtubule dynamics by promoting tubulin acetylation: acts by inhibiting the tubulin deacetylase activity of HDAC6 (PubMed:20308065, PubMed:23093407).
Also regulates cell migration: phosphorylation by ROCK1 inhibits interaction with HDAC6, resulting in decreased acetylation of tubulin and increased cell motility (PubMed:23093407).
Plays a role in cell proliferation by regulating the G1/S-phase transition (PubMed:23355470).
Involved in astral microtubule organization and mitotic spindle orientation during early stage of mitosis; this process is regulated by phosphorylation by LIMK2 (PubMed:22328514).

Biological Process

Biological Process astral microtubule organization Source:UniProtKB1 Publication
Biological Process cell division Source:UniProtKB-KW
Biological Process microtubule bundle formation Source:UniProtKB2 Publications
Biological Process microtubule nucleation by microtubule organizing center Source:UniProtKB1 Publication
Biological Process microtubule polymerization Source:UniProtKB1 Publication
Biological Process myelin assembly Source:UniProtKB
Biological Process negative regulation of tubulin deacetylation Source:UniProtKB2 Publications
Biological Process oligodendrocyte development Source:UniProtKB
Biological Process oligodendrocyte differentiation Source:UniProtKB
Biological Process positive regulation of myelination Source:UniProtKB
Biological Process positive regulation of protein polymerization Source:HGNC-UCL1 Publication
Biological Process positive regulation of protein-containing complex assembly Source:HGNC-UCL
Biological Process regulation of microtubule cytoskeleton organization Source:UniProtKB1 Publication

Cellular Location

Golgi outpost
Cytoplasm, cytoskeleton, microtubule organizing center
Cytoplasm, cytoskeleton
Nucleus
Cytoplasm, cytoskeleton, spindle
Specifically localizes to the postsynaptic Golgi apparatus region, also named Golgi outpost, which shapes dendrite morphology by functioning as sites of acentrosomal microtubule nucleation (By similarity).
Mainly localizes to the cytoskeleton (PubMed:18028908).
Also found in the nucleus; however, nuclear localization is unclear and requires additional evidences (PubMed:18028908).
Localizes to glial Lewy bodies in the brains of individuals with synucleinopathies (PubMed:15590652, PubMed:17027006).
During mitosis, colocalizes with LIMK2 at the mitotic spindle (PubMed:22328514).

PTM

Phosphorylated by LIMK1 on serine residues; phosphorylation may alter the tubulin polymerization activity (PubMed:17693641, PubMed:18028908).
Phosphorylation by LIMK2, but not LIMK1, regulates astral microtubule organization at early stage of mitosis (PubMed:22328514).
Phosphorylation by ROCK1 at Ser-32, Ser-107 and Ser-159 inhibits interaction with HDAC6, resulting in decreased acetylation of tubulin, increased cell motility and entry into S-phase (PubMed:23093407, PubMed:23355470).
Phosphorylation by CDK1 inhibits the microtubule polymerizing activity (PubMed:23355470).
Degraded by the proteasome; zinc-binding inhibits degradation by the proteasome.