| ID | Symbol | Description | Aliases |
| YGL137W | SEC27 | Essential beta'-coat protein of the COPI coatomer, involved in ER-to-Golgi and Golgi-to-ER transport; contains WD40 domains that mediate cargo selective interactions; 45% sequence identity to mammalian beta'-COP | | |
| YLR026C | SED5 | cis-Golgi t-SNARE syntaxin required for vesicular transport between the ER and the Golgi complex, binds at least 9 SNARE proteins | | |
| YGL145W | TIP20 | Peripheral membrane protein required for fusion of COPI vesicles with the ER, prohibits back-fusion of COPII vesicles with the ER, may act as a sensor for vesicles at the ER membrane | TIP1 | |
| YDL145C | COP1 | Alpha subunit of COPI vesicle coatomer complex, which surrounds transport vesicles in the early secretory pathway | RET1, SEC33, SOO1 | |
| YLR268W | SEC22 | R-SNARE protein; assembles into SNARE complex with Bet1p, Bos1p and Sed5p; cycles between the ER and Golgi complex; involved in anterograde and retrograde transport between the ER and Golgi; synaptobrevin homolog | SLY2, TSL26 | |
| YNL258C | DSL1 | Endoplasmic reticulum (ER)-localized peripheral membrane protein required for Golgi-to-ER retrograde traffic; component of the ER target site that interacts with coatomer, the major component of the COPI vesicle protein coat | | |
| YGL098W | USE1 | Essential SNARE protein localized to the ER, involved in retrograde traffic from the Golgi to the ER; forms a complex with the SNAREs Sec22p, Sec20p and Ufe1p | SLT1 | |
| YIL004C | BET1 | Type II membrane protein required for vesicular transport between the endoplasmic reticulum and Golgi complex; v-SNARE with similarity to synaptobrevins | SLY12 | |
| YDR189W | SLY1 | Hydrophilic protein involved in vesicle trafficking between the ER and Golgi; SM (Sec1/Munc-18) family protein that binds the tSNARE Sed5p and stimulates its assembly into a trans-SNARE membrane-protein complex | | |
| YOL086C | ADH1 | Alcohol dehydrogenase, fermentative isozyme active as homo- or heterotetramers; required for the reduction of acetaldehyde to ethanol, the last step in the glycolytic pathway | ADC1 | |
| YFR051C | RET2 | Delta subunit of the coatomer complex (COPI), which coats Golgi-derived transport vesicles; involved in retrograde transport between Golgi and ER | | |
| YNL287W | SEC21 | Gamma subunit of coatomer, a heptameric protein complex that together with Arf1p forms the COPI coat; involved in ER to Golgi transport of selective cargo | | |
| YDR498C | SEC20 | Membrane glycoprotein v-SNARE involved in retrograde transport from the Golgi to the ER; required for N- and O-glycosylation in the Golgi but not in the ER; forms a complex with the cytosolic Tip20p | | |
| YLR440C | SEC39 | Protein of unknown function proposed to be involved in protein secretion | | |
| YOR075W | UFE1 | t-SNARE required for ER membrane fusion and vesicular traffic, integral membrane protein that constitutes with Sec20p and Use1p the trimeric acceptor for R/v-SNAREs on Golgi-derived vesicles at the ER; part of Dsl1p complex | YOR29-26 | |
| YLR078C | BOS1 | v-SNARE (vesicle specific SNAP receptor), localized to the endoplasmic reticulum membrane and necessary for vesicular transport from the ER to the Golgi | SEC32 | |