Component of the COPII coat, that covers ER-derived vesicles involved in transport from the endoplasmic reticulum to the Golgi apparatus. COPII acts in the cytoplasm to promote the transport of secretory, plasma membrane, and vacuolar proteins from the endoplasmic reticulum to the Golgi complex. COPII is composed of at least five proteins: the SEC23/24 complex, the SEC13/31 complex and SAR1. Interacts with GRH1. Present with 1720 molecules/cell in log phase SD medium. Belongs to the SEC23/SEC24 family. SEC24 subfamily.