TRAPPC3 (trafficking protein particle complex subunit 3) is a component of the evolutionarily conserved TRAPP (Transport Protein Particle) complex that functions as a key regulator of vesicular trafficking pathways. As a core subunit of TRAPP complexes, TRAPPC3 facilitates endoplasmic reticulum-to-Golgi transport by participating in vesicle tethering and guanyl-nucleotide exchange factor activity 1. The protein is essential for proper trafficking of various cargo proteins, including different collagen types, where it works alongside other factors like SAR1, TANGO1, and SLY1/SCFD1 1. TRAPPC3 physically interacts with other TRAPP subunits, particularly TRAPPC6B, and this interaction is crucial for TRAPP II complex stability and function 2. Disruption of TRAPPC3-TRAPPC6B interactions leads to reduced TRAPP complex integrity and impaired Golgi trafficking 2. The protein shows structural similarity to BET3, another TRAPP subunit, suggesting potential heterodimerization capabilities 3. TRAPPC3 has been identified as a candidate gene in ciliopathy disorders, highlighting its potential role in ciliary function 4. Additionally, TRAPPC3 expression is regulated by hypoxia and NRF-1 transcription factor, suggesting involvement in cellular stress responses and neurite outgrowth 56.