Protein: Small COPII coat GTPase sar1 (EC 3.6.5.-) (Q01475)
Organism: Schizosaccharomyces pombe (strain 972 / ATCC 24843) (Fission yeast)
Function: Small GTPase component of the coat protein complex II (COPII) which promotes the formation of transport vesicles from the endoplasmic reticulum (ER). The coat has two main functions, the physical deformation of the endoplasmic reticulum membrane into vesicles and the selection of cargo molecules. Sar1 controls the coat assembly in a stepwise manner. Activated sar1-GTP binds to membranes first and recruits the SEC23/24 complex. These sec23/24-sar1 prebudding intermediates are then collected by the sec13/31 complex as subunits polymerize to form coated transport vesicles. Conversion to sar1-GDP triggers coat release and recycles COPII subunits (By similarity).
Subcellular location: Cytoplasmic vesicle, COPII-coated vesicle membrane {ECO:0000250}; Peripheral membrane protein {ECO:0000250}; Cytoplasmic side {ECO:0000250}. Endoplasmic reticulum membrane {ECO:0000250}; Peripheral membrane protein {ECO:0000250}; Cytoplasmic side {ECO:0000250}. Golgi apparatus membrane {ECO:0000250}; Peripheral membrane protein {ECO:0000250}; Cytoplasmic side {ECO:0000250}.
Sequence: MFIINWFYDALAMLGLVNKHAKMLFLGLDNAGKTTLLHMLKNDRLAVMQPTLHPTSEELAIGNVRFTTFDLGGHQQARRLWRDYFPEVNGIVYLVDCCDFERLSESKAELDALLAMEELARVPFLILGNKIDAPGAISEDELKAALGLYQTTGKGVSKPVPGIRPIEVFMCSVVLRQGYGEGFKWLAQYV
InterPro domains: - IPR006689: Small GTPase superfamily, ARF/SAR type (family) [4-190]
- IPR006687: Small GTPase superfamily, SAR1-type (family) [1-190]
- IPR027417: P-loop containing nucleoside triphosphate hydrolase (homologous_superfamily) [1-190]
- IPR005225: Small GTP-binding domain (domain) [19-141]
Interaction partners: - Membrane glycoprotein spo14
- Protein transport protein sec31
- Protein transport protein sec13
- Protein transport protein sec24
- Protein transport protein sec23-1
- Protein transport protein sec23-2
- COPII coat assembly protein sec16
- Triacylglycerol lipase ptl2
- Probable coatomer subunit gamma
- Uncharacterized protein C4.03c
Gene Ontology annotations:
Molecular Function (MF): GO:0003674 (molecular function), GO:0005488 (binding), GO:0003824 (catalytic activity), GO:0016787 (hydrolase activity), GO:0005515 (protein binding), GO:0016817 (hydrolase activity, acting on acid anhydrides), GO:0016818 (hydrolase activity, acting on acid anhydrides, in phosphorus-containing anhydrides), GO:0016462 (pyrophosphatase activity), GO:0017111 (ribonucleoside triphosphate phosphatase activity), GO:0003924 (GTPase activity)
Biological Process (BP): GO:0008150 (biological process), GO:0009987 (cellular process), GO:0051179 (localization), GO:0051234 (establishment of localization), GO:0051641 (cellular localization), GO:0046907 (intracellular transport), GO:0051649 (establishment of localization in cell), GO:0006810 (transport), GO:0006888 (endoplasmic reticulum to Golgi vesicle-mediated transport), GO:0016192 (vesicle-mediated transport), GO:0048193 (Golgi vesicle transport)
Cellular Component (CC): GO:0005575 (cellular component), GO:0032991 (protein-containing complex), GO:0110165 (cellular anatomical entity), GO:0005622 (intracellular anatomical structure), GO:0043226 (organelle), GO:0016020 (membrane), GO:0005737 (cytoplasm), GO:0098796 (membrane protein complex), GO:0012505 (endomembrane system), GO:0031090 (organelle membrane), GO:0030117 (membrane coat), GO:0031410 (cytoplasmic vesicle), GO:0043229 (intracellular organelle), GO:0048475 (coated membrane), GO:0043227 (membrane-bounded organelle), GO:0030133 (transport vesicle), GO:0030658 (transport vesicle membrane), GO:0030120 (vesicle coat), GO:0030135 (coated vesicle), GO:0043231 (intracellular membrane-bounded organelle), GO:0098588 (bounding membrane of organelle), GO:0031982 (vesicle), GO:0012506 (vesicle membrane), GO:0030659 (cytoplasmic vesicle membrane), GO:0012507 (ER to Golgi transport vesicle membrane), GO:0030127 (COPII vesicle coat), GO:0030662 (coated vesicle membrane), GO:0030134 (COPII-coated ER to Golgi transport vesicle), GO:0097708 (intracellular vesicle)