Structural highlights
Disease
[SC23A_HUMAN] Defects in SEC23A are the cause of craniolenticulosutural dysplasia (CLSD) [MIM:607812]; also known as cranio-lenticulo-sutural dysplasia. CLSD is an autosomal recessive syndrome characterized by late-closing fontanels, sutural cataracts, facial dysmorphisms and skeletal defects.[1]
Function
[SC23A_HUMAN] 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. [SC22B_HUMAN] SNARE involved in targeting and fusion of ER-derived transport vesicles with the Golgi complex as well as Golgi-derived retrograde transport vesicles with the ER.[2] [SC24A_HUMAN] 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.
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Genomic analysis shows that the increased complexity of trafficking pathways in mammalian cells involves an expansion of the number of SNARE, Rab and COP proteins. Thus, the human genome encodes four forms of Sec24, the cargo selection subunit of the COPII vesicular coat, and this is proposed to increase the range of cargo accommodated by human COPII-coated vesicles. In this study, we combined X-ray crystallographic and biochemical analysis with functional assays of cargo packaging into COPII vesicles to establish molecular mechanisms for cargo discrimination by human Sec24 subunits. A conserved IxM packaging signal binds in a surface groove of Sec24c and Sec24d, but the groove is occluded in the Sec24a and Sec24b subunits. Conversely, LxxLE class transport signals and the DxE signal of VSV glycoprotein are selectively bound by Sec24a and Sec24b subunits. A comparative analysis of crystal structures of the four human Sec24 isoforms establishes the structural determinants for discrimination among these transport signals, and provides a framework to understand how an expansion of coat subunits extends the range of cargo proteins packaged into COPII-coated vesicles.
Structural basis of cargo membrane protein discrimination by the human COPII coat machinery.,Mancias JD, Goldberg J EMBO J. 2008 Nov 5;27(21):2918-28. Epub 2008 Oct 9. PMID:18843296[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Boyadjiev SA, Fromme JC, Ben J, Chong SS, Nauta C, Hur DJ, Zhang G, Hamamoto S, Schekman R, Ravazzola M, Orci L, Eyaid W. Cranio-lenticulo-sutural dysplasia is caused by a SEC23A mutation leading to abnormal endoplasmic-reticulum-to-Golgi trafficking. Nat Genet. 2006 Oct;38(10):1192-7. Epub 2006 Sep 17. PMID:16980979 doi:10.1038/ng1876
- ↑ Nakajima K, Hirose H, Taniguchi M, Kurashina H, Arasaki K, Nagahama M, Tani K, Yamamoto A, Tagaya M. Involvement of BNIP1 in apoptosis and endoplasmic reticulum membrane fusion. EMBO J. 2004 Aug 18;23(16):3216-26. Epub 2004 Jul 22. PMID:15272311 doi:10.1038/sj.emboj.7600333
- ↑ Mancias JD, Goldberg J. Structural basis of cargo membrane protein discrimination by the human COPII coat machinery. EMBO J. 2008 Nov 5;27(21):2918-28. Epub 2008 Oct 9. PMID:18843296 doi:http://dx.doi.org/10.1038/emboj.2008.208
