YPT1/YFL038C Summary Help

Standard Name YPT1 1
Systematic Name YFL038C
Feature Type ORF, Verified
Description Rab family GTPase; involved in the ER-to-Golgi step of the secretory pathway; complex formation with the Rab escort protein Mrs6p is required for prenylation of Ypt1p by protein geranylgeranyltransferase type II (Bet2p-Bet4p); binds to unspliced HAC1 mRNA; regulates unfolded protein response (UPR) by promoting the decay of HAC1 RNA (2, 3, 4 and see Summary Paragraph)
Also known as: YP2
Name Description Yeast Protein Two 1
Chromosomal Location
ChrVI:55986 to 55366 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Genetic position: -59 cM
Gene Ontology Annotations All YPT1 GO evidence and references
  View Computational GO annotations for YPT1
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 1 genes
Classical genetics
Large-scale survey
reduction of function
228 total interaction(s) for 133 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 18
  • Affinity Capture-RNA: 7
  • Affinity Capture-Western: 17
  • Biochemical Activity: 4
  • Co-crystal Structure: 2
  • Co-localization: 1
  • Co-purification: 3
  • FRET: 1
  • PCA: 8
  • Protein-RNA: 1
  • Reconstituted Complex: 9
  • Two-hybrid: 21

Genetic Interactions
  • Dosage Growth Defect: 3
  • Dosage Lethality: 5
  • Dosage Rescue: 29
  • Negative Genetic: 46
  • Phenotypic Enhancement: 1
  • Phenotypic Suppression: 8
  • Positive Genetic: 1
  • Synthetic Growth Defect: 7
  • Synthetic Lethality: 31
  • Synthetic Rescue: 5

Expression Summary
Length (a.a.) 206
Molecular Weight (Da) 23,214
Isoelectric Point (pI) 5.01
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrVI:55986 to 55366 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Genetic position: -59 cM
Last Update Coordinates: 2011-02-03 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..621 55986..55366 2011-02-03 1996-07-31
Retrieve sequences
Analyze Sequence
S288C only
S288C vs. other species
S288C vs. other strains
External Links All Associated Seq | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | UniProtKB
Primary SGDIDS000001856

Rab proteins are small Ras-related GTPases that function in multiple stages in membrane traffic. Rabs continuously cycle between the cytosol and membranes. The GDP-bound form of the Rab is complexed with guanine nucleotide dissociation inhibitor(GDI) in the cytosol and are recruited to the membranes with the help of GDF (GDI Displacement Factor) and by their prenylation by geranylgeranyl transferase II (GGTase II). The membrane-bound Rab is activated to the GTP-bound form by the guanine nucleotide exchange factors (GEFs) which then goes on to interact with downstream effectors. The GTPase-activating protein (GAP) stimulates the hydrolysis of GTP to GDP to inactivate the Rab. Eleven Rabs have been identified in yeast and more than 60 in mammalian cells (reviewed in 5, 6, 7).

Ypt1p is a Rab GTPase required for vesicle docking and fidelity of vesicle targeting during ER to Golgi and intra Golgi trafficking (8, reviewed in 6). The docking and tethering step, mediated by Ypt1p, Uso1p, the Sec34/35 complex and the TRAPP complex, occurs before SNARE complex assembly and vesicle fusion (9, 10, 3). Activation of Ypt1p to the GTP-bound form is mediated by the guanine nucleotide exchange factor (GEF) TRAPP1 complex. The GTP-bound Ypt1p regulates the assembly of the SNARE proteins consisting of Sed5p, Bet1p, Bos1p and Sly1p. Gyp1p, the GTPase-activating protein (GAP) stimulates the hydrolysis of GTP to GDP and serves as a negative regulator of Ypt1p(11)

Last updated: 2010-05-18 Contact SGD

References cited on this page View Complete Literature Guide for YPT1
1) Gallwitz D, et al.  (1983) A yeast gene encoding a protein homologous to the human c-has/bas proto-oncogene product. Nature 306(5944):704-7
2) Miaczynska M, et al.  (1997) The yeast Rab escort protein binds intracellular membranes in vivo and in vitro. J Biol Chem 272(27):16972-7
3) Morsomme P and Riezman H  (2002) The Rab GTPase Ypt1p and tethering factors couple protein sorting at the ER to vesicle targeting to the Golgi apparatus. Dev Cell 2(3):307-17
4) Tsvetanova NG, et al.  (2012) The Yeast Rab GTPase Ypt1 Modulates Unfolded Protein Response Dynamics by Regulating the Stability of HAC1 RNA. PLoS Genet 8(7):e1002862
5) Cai H, et al.  (2007) Coats, tethers, Rabs, and SNAREs work together to mediate the intracellular destination of a transport vesicle. Dev Cell 12(5):671-82
6) Grosshans BL, et al.  (2006) Rabs and their effectors: achieving specificity in membrane traffic. Proc Natl Acad Sci U S A 103(32):11821-7
7) Bialek-Wyrzykowska U, et al.  (2000) Low levels of Ypt protein prenylation cause vesicle polarization defects and thermosensitive growth that can be suppressed by genes involved in cell wall maintenance. Mol Microbiol 35(6):1295-311
8) Jedd G, et al.  (1995) The Ypt1 GTPase is essential for the first two steps of the yeast secretory pathway. J Cell Biol 131(3):583-90
9) Cai Y, et al.  (2008) The structural basis for activation of the Rab Ypt1p by the TRAPP membrane-tethering complexes. Cell 133(7):1202-13
10) Cao X, et al.  (1998) Initial docking of ER-derived vesicles requires Uso1p and Ypt1p but is independent of SNARE proteins. EMBO J 17(8):2156-65
11) Du LL, et al.  (1998) Identification of a Sec4p GTPase-activating protein (GAP) as a novel member of a Rab GAP family. J Biol Chem 273(6):3253-6