High impact information on SEC24

• We show that the same site is conserved as a cargo-interaction domain on the Sec24p homolog Lst1p, which only packages a subset of the cargoes recognized by Sec24p [1].
• We identified a site on Sec24p that recognizes the v-SNARE Bet1p and show that packaging of a number of cargo molecules is disrupted when mutations are introduced at this site [1].
• Multiple cargo binding sites on the COPII subunit Sec24p ensure capture of diverse membrane proteins into transport vesicles [1].
• The cytosolic yeast proteins Sec13p-Sec31p, Sec23p-Sec24p, and the small GTP-binding protein Sar1p generate protein transport vesicles by forming the membrane coat termed COPII [2].
• A new structural study now provides breathtaking molecular insights into the formation of the Sec23-Sec24-Sar1 pre-budding complex and into COPII coat assembly [3].

Biological context of SEC24

• Based on the finding that ANU1 is identical to SEC24, we confirmed a temperature-sensitive protein transport from the ER to the Golgi in anu1-1/sec24-20 cells [4].
• Overexpression of SFB2, a SEC24 homologue with 56% identity, partially suppressed not only the mutant phenotype of sec24-20 cells but also rescued the SEC24-disrupted cells [4].
• Three other coatmer protein (COPII) mutants, sec16, sec23, and sec24, were also defective in autophagy [5].
• Destruction by mutagenesis of a potential zinc finger within the N-terminal half of Sec24p led to a nonfunctional protein that was still able to bind Sec23p and Sed5p [6].
• These data suggest that when entering into mitosis, the COPII component Sec24p is simultaneously deglycosylated and phosphorylated, a process which may contribute to the observed mitotic ER-to-Golgi traffic block [7].

Anatomical context of SEC24

• LST1 is a SEC24 homologue used for selective export of the plasma membrane ATPase from the endoplasmic reticulum [8].
• Sec24p and Iss1p function interchangeably in transport vesicle formation from the endoplasmic reticulum in Saccharomyces cerevisiae [9].
• These results suggest that Lst1p and Sec24p cooperate in the packaging of Pma1p and support the view that biosynthetic precursors of plasma membrane proteins must be sorted into ER-derived transport vesicles [10].
• We show that Lst1p can function as a COPII subunit independently of Sec24p on native ER membranes and on synthetic liposomes [11].
• Surprisingly, vesicles generated with the mutant Sec24p were unable to fuse with the Golgi apparatus [12].

Associations of SEC24 with chemical compounds

• Endoplasmic reticulum exit of a secretory glycoprotein in the absence of sec24p family proteins in yeast [13].
• Using mutants defective in the heavy chain of clathrin and in several subunits of the COPI and the COPII complexes, we found that clathrin, as well as two cytosolic subunits of COPII, Sec23p and Sec24p, could be involved in internalization of the yeast maltose transporter [14].

Physical interactions of SEC24

• The Sec23p/Sec24p complex functions as a component of the COPII coat in vesicle transport from the endoplasmic reticulum [9].
• Here we use two-hybrid and coprecipitation assays to demonstrate that the essential COPII protein Sec24p binds to the central region of Sec16p [15].
• Specific interaction of the yeast cis-Golgi syntaxin Sed5p and the coat protein complex II component Sec24p of endoplasmic reticulum-derived transport vesicles [6].

Other interactions of SEC24

• Sfb2p, a yeast protein related to Sec24p, can function as a constituent of COPII coats required for vesicle budding from the endoplasmic reticulum [4].
• Abundant proteins in the purified vesicles produced with Sec23p/Iss1p were indistinguishable from those in the regular COPII vesicles produced with Sec23p/Sec24p [9].
• Budding of transport vesicles from the endoplasmic reticulum in yeast requires the formation, at the budding site, of a coat protein complex (COPII) that consists of two heterodimeric subcomplexes (Sec23p/Sec24p and Sec13p/Sec31p) and the Sar1 GTPase [16].
• Using temperature-sensitive sec24-1 mutants, we showed previously that a secretory glycoprotein, Hsp150, does not require functional Sec24p for ER exit [13].
• First, we map onto Sec31p binding regions for Sec16p, Sec23p, Sec24p, and Sec13p [17].

Analytical, diagnostic and therapeutic context of SEC24

• Using affinity chromatography and two-hybrid analyses, we found that the essential COPII component Sec24p, but not Sec23p, binds to the cis-Golgi syntaxin Sed5p [6].
• Peptide sequence analysis of cytosolic proteins that are specifically bound to GST-Yip1A revealed, among other proteins, mammalian COPII components Sec23 and Sec24 [18].

References