TMED9 Protein, Human (HEK293, His)

TMED9, a protein intricately involved in vesicular protein trafficking, predominantly operates within the early secretory pathway, particularly in COPI vesicle-mediated retrograde transport, facilitating coatomer recruitment to membranes. It enhances the coatomer-dependent activity of ARFGAP2 and plays a pivotal role in the specific retention of p24 complexes in cis-Golgi membranes, contributing notably to the coupled localization of TMED2 and TMED10 in the cis-Golgi network. Beyond its involvement in retrograde transport, TMED9 is implicated in the organization of intracellular membranes, including the ER-Golgi intermediate compartment and the Golgi apparatus. It further participates in the ER localization of PTPN2 isoform PTPB. TMED9 exhibits a dynamic oligomeric state, existing as a monomer and homodimer in the endoplasmic reticulum, with a predominantly monomeric state in the endoplasmic reticulum-Golgi intermediate compartment and cis-Golgi network. Oligomerization likely occurs with other members of the EMP24/GP25L family, such as TMED2, TMED7, and TMED10. Additionally, TMED9 engages in specific interactions with TMED5, COPG1, PTPN2, SPAST, and STX17, underscoring its multifaceted involvement in intracellular processes.