The SEC23B gene provides instructions for making one component of a large group of interacting proteins called coat protein complex II (COPII). COPII is involved in the formation of vesicles, which are small sac-like structures that transport proteins and other materials within cells. Specifically, COPII triggers the formation of vesicles in a cellular structure called the endoplasmic reticulum (ER), which is involved in protein processing and transport. These COPII vesicles carry proteins that are destined to be exported out of cells (secreted).
The SEC23B protein is very similar to the protein produced from a related gene, SEC23A. These proteins are both components of COPII, and they appear to have overlapping functions. In most types of cells, if one of these proteins is missing, the other may be able to compensate for the loss. However, research indicates that the SEC23B protein may have a unique function in developing red blood cells (erythroblasts).
Health Conditions Related to Genetic Changes
Congenital dyserythropoietic anemia
At least 20 mutations in the SEC23B gene have been identified in people with congenital dyserythropoietic anemia (CDA) type II. Most of these mutations change single protein building blocks (amino acids) in the SEC23B protein. Other mutations delete genetic material from the SEC23B gene or alter the way the gene's instructions are used to make the SEC23B protein. The mutations responsible for CDA type II likely disrupt the function of the SEC23B protein. However, researchers suspect that these mutations do not completely eliminate the function of the protein, which appears to be essential for life.
It is unclear how SEC23B mutations cause the characteristic features of CDA type II. The abnormal SEC23B protein leads to the production of erythroblasts that are unusually shaped and may have extra nuclei. These defective erythroblasts cannot develop into functional mature red blood cells. The resulting shortage of healthy red blood cells leads to the characteristic signs and symptoms of anemia, as well as complications including an enlarged liver and spleen (hepatosplenomegaly) and an abnormal buildup of iron that can damage the body's organs.More About This Health Condition
Other Names for This Gene
- Sec23 homolog B
- Sec23 homolog B (S. cerevisiae)
- Sec23 homolog B, COPII coat complex component
- SEC23-like protein B
- SEC23-related protein B
- transport protein SEC23B
Additional Information & Resources
Tests Listed in the Genetic Testing Registry
Scientific Articles on PubMed
Catalog of Genes and Diseases from OMIM
- Denecke J, Marquardt T. Congenital dyserythropoietic anemia type II (CDAII/HEMPAS): where are we now? Biochim Biophys Acta. 2009 Sep;1792(9):915-20. doi: 10.1016/j.bbadis.2008.12.005. Epub 2008 Dec 25. Review. Citation on PubMed
- Fromme JC, Orci L, Schekman R. Coordination of COPII vesicle trafficking by Sec23. Trends Cell Biol. 2008 Jul;18(7):330-6. doi: 10.1016/j.tcb.2008.04.006. Epub 2008 Jun 3. Review. Citation on PubMed
- Hughes H, Stephens DJ. Assembly, organization, and function of the COPII coat. Histochem Cell Biol. 2008 Feb;129(2):129-51. Epub 2007 Dec 4. Review. Citation on PubMed or Free article on PubMed Central
- Schwarz K, Iolascon A, Verissimo F, Trede NS, Horsley W, Chen W, Paw BH, Hopfner KP, Holzmann K, Russo R, Esposito MR, Spano D, De Falco L, Heinrich K, Joggerst B, Rojewski MT, Perrotta S, Denecke J, Pannicke U, Delaunay J, Pepperkok R, Heimpel H. Mutations affecting the secretory COPII coat component SEC23B cause congenital dyserythropoietic anemia type II. Nat Genet. 2009 Aug;41(8):936-40. doi: 10.1038/ng.405. Epub 2009 Jun 28. Citation on PubMed