Regucalcin Gene Promotor Region Related Protein (RGPR)

SEC16B is a mammalian homolog of S. cerevisiae Sec16 that is required for organization of transitional endoplasmic reticulum (ER) sites and protein export . The deduced 1,060-amino acid human SEC16B protein has a calculated molecular mass of 117 kD. Northern blot analysis of rat tissues detected a 4.5-kb transcript in liver, kidney, heart, spleen, and brain. SEC16B contains predicted phosphorylation, N-myristoylation, N-glycosylation, and amidation sites, as well as a leucine zipper motif and a hydrophobic N-terminal region.SEC16B is required for organization of transitional ER sites and ER export in HeLa cells and that the SEC16B N-terminal region is required for transitional ER site localization. Coimmunoprecipitation studies showed that SEC16B and SEC16A form a heteromeric complex.