SEC16 Homolog A (SEC16A)

SEC16A is a peripheral membrane protein that defines ERES in mammalian cells and is required for protein transport from ER to Golgi.The predicted 2,357 amino acid protein contains 3 proline-rich regions and 1 tyrosine-rich region. SEC16A shares 19.8% amino acid identity with S. cerevisiae Sec16a. By GST pull-down assay, the authors identified mouse Sec16a, which they called p250, as a Sec23a -interacting protein. Immunofluorescence microscopy localized SEC16A to ERES, where it colocalized with COPII component SEC31A and with ER-Golgi intermediate compartment marker ERGIC53 (LMAN1).SAR1 is required for SEC16A association with ERES and formation of the ERES scaffold and that there is a stoichiometric level of SEC16A required for optimal ER-to-Golgi protein transport.