The Genetic Basis of a Craniofacial Disease Provides Insight into COPII Coat Assembly

J. Christopher Fromme, Mariella Ravazzola, Susan Hamamoto, Mohammed Al-Balwi, Wafaa Eyaid, Simeon Boyd, Pierre Cosson, Randy Schekman, Lelio Orci

Research output: Contribution to journalArticle

127 Scopus citations

Abstract

Proteins trafficking through the secretory pathway must first exit the endoplasmic reticulum (ER) through membrane vesicles created and regulated by the COPII coat protein complex. Cranio-lenticulo-sutural dysplasia (CLSD) was recently shown to be caused by a missense mutation in SEC23A, a gene encoding one of two paralogous COPII coat proteins. We now elucidate the molecular mechanism underlying this disease. In vitro assays reveal that the mutant form of SEC23A poorly recruits the Sec13-Sec31 complex, inhibiting vesicle formation. Surprisingly, this effect is modulated by the Sar1 GTPase paralog used in the reaction, indicating distinct affinities of the two human Sar1 paralogs for the Sec13-Sec31 complex. Patient cells accumulate numerous tubular cargo-containing ER exit sites devoid of observable membrane coat, likely representing an intermediate step in COPII vesicle formation. Our results indicate that the Sar1-Sec23-Sec24 prebudding complex is sufficient to form cargo-containing tubules in vivo, whereas the Sec13-Sec31 complex is required for membrane fission.

Original languageEnglish (US)
Pages (from-to)623-634
Number of pages12
JournalDevelopmental Cell
Volume13
Issue number5
DOIs
StatePublished - Nov 6 2007

Keywords

  • CELLBIO
  • HUMDISEASE

ASJC Scopus subject areas

  • Developmental Biology

Fingerprint Dive into the research topics of 'The Genetic Basis of a Craniofacial Disease Provides Insight into COPII Coat Assembly'. Together they form a unique fingerprint.

  • Cite this

    Fromme, J. C., Ravazzola, M., Hamamoto, S., Al-Balwi, M., Eyaid, W., Boyd, S., Cosson, P., Schekman, R., & Orci, L. (2007). The Genetic Basis of a Craniofacial Disease Provides Insight into COPII Coat Assembly. Developmental Cell, 13(5), 623-634. https://doi.org/10.1016/j.devcel.2007.10.005