PMID: 27569046

Authors:

Nagae M, Hirata T, Morita-Matsumoto K, Theiler R, Fujita M, Kinoshita T, Yamaguchi Y

Title:

3D Structure and Interaction of p24beta and p24delta Golgi Dynamics Domains: Implication for p24 Complex Formation and Cargo Transport.

Journal:

J Mol Biol. 2016 Aug 25. pii: S0022-2836(16)30342-4. doi:, 10.1016/j.jmb.2016.08.023.

Abstract:

The p24 family consists of four subfamilies (p24alpha, p24beta, p24gamma, and p24delta), and the proteins are thought to form hetero-oligomeric complexes for efficient transport of cargo proteins from the endoplasmic reticulum to the Golgi apparatus. The proteins possess a conserved luminal Golgi dynamics (GOLD) domain, whose functions are largely unknown. Here, we present structural and biochemical studies of p24beta1 and p24delta1 GOLD domains. Use of GOLD domain-deleted mutants revealed that the GOLD domain of p24delta1 is required for proper p24 hetero-oligomeric complex formation and efficient transport of GPI-anchored proteins. The p24beta1 and p24delta1 GOLD domains share a common beta-sandwich fold with a characteristic intrasheet disulfide bond. The GOLD domain of p24delta1 crystallized as dimers, allowing the analysis of a homophilic interaction site. Surface plasmon resonance and solution NMR analyses revealed that p24beta1 and p24delta1 GOLD domains interact weakly (Kd= ~10-4M). Bi-protein titration provided interaction site maps. We propose that the heterophilic interaction of p24 GOLD domains contributes to the formation of the p24 hetero-oligomeric complex and to efficient cargo transport.