TVP23C

Model summary

A multi-pass membrane adaptor in human cells that resides in the Golgi apparatus and organizes vesicle traffic. By embedding a TVP23-like scaffold within the Golgi membrane, it concentrates binding interfaces for coats, tethers, and sorting factors, thereby capturing and recycling transport vesicles and sustaining efficient cargo flow through the Golgi network. Its mechanism relies on multivalent protein interactions rather than catalysis, coordinating vesicle budding, tethering, and fusion to maintain intracellular transport.

Predicted Gene Ontology terms

1. 01

   I begin with the InterPro architecture: a single family signature IPR008564 (Golgi apparatus membrane protein TVP23-like, residues 8–205) spans essentially the entire polypeptide, indicating a compact, multi-pass membrane protein specialized for Golgi-resident trafficking functions.

   TVP23-like families are characterized by several tightly packed transmembrane helices that create a scaffold for vesicle capture and cargo sorting within the Golgi apparatus membrane. The dominance of a single, full-length TVP23-like family domain and the absence of soluble catalytic modules argue that this protein operates as a membrane-embedded adaptor rather than an enzyme.

2. 02

   This architecture causally supports a molecular function centered on multivalent protein binding (GO:0005515).

   Multi-pass Golgi adaptors typically present short cytosolic loops that bind coat components and sorting factors, and luminal loops that can engage cargo determinants. The TVP23-like fold provides the membrane-anchored platform that concentrates binding sites for cytosolic trafficking machinery and luminal cargo, thereby enforcing a binding-driven mechanism rather than catalysis.

3. 03

   From this binding-centric mechanism, the biological process follows: vesicle-mediated transport (GO:0016192).

   A TVP23-like scaffold embedded in the Golgi membrane is positioned to capture and recycle transport vesicles, to coordinate anterograde and retrograde flux, and to maintain the fidelity of cargo flow through the Golgi stack. By stabilizing interactions with coats and tethers, the protein directly drives vesicle budding, tethering, and fusion cycles that underpin intracellular trafficking.

4. 04

   The cellular context is dictated by the domain family and topology: a multi-pass membrane protein resident of the Golgi apparatus membrane, consistent with a core localization to the Golgi apparatus (GO:0005794).

   The membrane-integrated architecture and the experimentally observed multi-pass nature together place the protein as an integral component of the Golgi membrane, where it orchestrates vesicle traffic.

5. 05

   Mechanistically, I hypothesize that the protein forms a Golgi-embedded adaptor hub.

   Its transmembrane bundle nucleates assembly of cytosolic coat complexes and tethering factors, while luminal loops help retain or recycle specific cargo. Likely interaction partners include ARF-family GTPases and their effectors that regulate Golgi coats, clathrin adaptors for intra-Golgi and post-Golgi routes, and tethering complexes that capture incoming vesicles. Through these assemblies, the protein stabilizes vesicle formation and targeting, ensuring efficient cargo flow through the Golgi network.