Involvement of the penta-EF-hand protein Pef1p in the Ca2+-dependent regulation of COPII subunit assembly in Saccharomyces cerevisiae

• Published in: PloS one 2012-07, Vol.7 (7), p.e40765-e40765
• Main Authors: Yoshibori, Mariko, Yorimitsu, Tomohiro, Sato, Ken
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Assembly; Baking yeast; Biological Transport; Biology; Calcium - metabolism; Calcium ions; Calcium signalling; Calcium-binding protein; Calcium-Binding Proteins - chemistry; Calcium-Binding Proteins - genetics; Calcium-Binding Proteins - metabolism; Cell Membrane - metabolism; Coat protein; COP-Coated Vesicles - metabolism; EF-hand; EF-hand protein; Endoplasmic reticulum; Free form; Gene Expression; Golgi apparatus; Hand protein; Homology; Life sciences; Lipids; Mammals; Molecular Sequence Data; Multiprotein Complexes - metabolism; Nuclear Pore Complex Proteins - metabolism; Physiology; Protein Binding; Protein Transport; Proteins; Regulation; Saccharomyces cerevisiae; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins - chemistry; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - metabolism; Sequence Alignment; Trends; Vesicular Transport Proteins - metabolism; Yeast
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0040765

Although it is well established that the coat protein complex II (COPII) mediates the transport of proteins and lipids from the endoplasmic reticulum (ER) to the Golgi apparatus, the regulation of the vesicular transport event and the mechanisms that act to counterbalance the vesicle flow between the ER and Golgi are poorly understood. In this study, we present data indicating that the penta-EF-hand Ca(2+)-binding protein Pef1p directly interacts with the COPII coat subunit Sec31p and regulates COPII assembly in Saccharomyces cerevisiae. ALG-2, a mammalian homolog of Pef1p, has been shown to interact with Sec31A in a Ca(2+)-dependent manner and to have a role in stabilizing the association of the Sec13/31 complex with the membrane. However, Pef1p displayed reversed Ca(2+) dependence for Sec13/31p association; only the Ca(2+)-free form of Pef1p bound to the Sec13/31p complex. In addition, the influence on COPII coat assembly also appeared to be reversed; Pef1p binding acted as a kinetic inhibitor to delay Sec13/31p recruitment. Our results provide further evidence for a linkage between Ca(2+)-dependent signaling and ER-to-Golgi trafficking, but its mechanism of action in yeast seems to be different from the mechanism reported for its mammalian homolog ALG-2.