Trafficking protein particle complex subunit 4 (TRAPPC4)

Trafficking protein particle complex subunit 4 (TRAPPC4) is a core component of the TRAPP (Transport Protein Particle) complex involved in vesicular trafficking, specifically mediating transport from the endoplasmic reticulum to the Golgi apparatus. It functions as a guanine nucleotide exchange factor (GEF) for Rab/Ypt GTPases, facilitating multiple stages of intracellular vesicle transport and autophagy. In cancer, TRAPPC4 interacts with ERK2 to regulate signaling relevant for cell proliferation and apoptosis and acts as a scaffold in recycling endosomes to maintain cell surface PD-L1 levels, influencing immune checkpoint therapeutic efficacy. Genetic defects in TRAPPC4 disrupt TRAPP complex stability, causing severe neurodevelopmental disorders such as epilepsy, microcephaly, and syndromic intellectual disability[1][2][3][4][5].

Other names

SynbindinTRS23 homologHematopoietic stem/progenitor cell protein 172SBDNCGI-104HSPC172PTD009TRS23SYNBINDINNEDESBA

Modulation of TRAPPC4 activity could impact PD-L1 cell surface expression, thus altering immune checkpoint blockade efficacy[2]. By affecting ERK1/2 signaling, could theoretically change tumor susceptibility to ERK/MAPK pathway inhibitors[2]. Targeting TRAPPC4 in neurodevelopmental disease could (hypothetically) restore vesicular trafficking in affected patients, but no such specific drugs are described in current literature.