BOI1/YBL085W Summary Help

Standard Name BOI1 1, 2
Systematic Name YBL085W
Alias GIN7 , BOB1
Feature Type ORF, Verified
Description Protein implicated in polar growth; functionally redundant with Boi2p; interacts with bud-emergence protein Bem1p; contains an SH3 (src homology 3) domain and a PH (pleckstrin homology) domain; relocalizes from bud neck to cytoplasm upon DNA replication stress; BOI1 has a paralog, BOI2, that arose from the whole genome duplication (3, 4, 5 and see Summary Paragraph)
Name Description Bem1 (One) Interacting protein 3
Chromosomal Location
ChrII:63876 to 66818 | ORF Map | GBrowse
Gene Ontology Annotations All BOI1 GO evidence and references
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 2 genes
Classical genetics
Large-scale survey
124 total interaction(s) for 92 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 18
  • Affinity Capture-RNA: 2
  • Affinity Capture-Western: 3
  • Biochemical Activity: 2
  • PCA: 1
  • Protein-peptide: 2
  • Two-hybrid: 61

Genetic Interactions
  • Dosage Rescue: 5
  • Negative Genetic: 15
  • Phenotypic Enhancement: 4
  • Phenotypic Suppression: 1
  • Positive Genetic: 4
  • Synthetic Growth Defect: 5
  • Synthetic Lethality: 1

Expression Summary
Length (a.a.) 980
Molecular Weight (Da) 109,294
Isoelectric Point (pI) 9.89
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrII:63876 to 66818 | ORF Map | GBrowse
Last Update Coordinates: 2011-02-03 | Sequence: 1997-01-28
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..2943 63876..66818 2011-02-03 1997-01-28
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 SGDIDS000000181

The Boi1 protein and its functionally redundant homolog Boi2p have been implicated in actin cytoskeleton reorganization and establishment of cell polarity (2, 1). boi1 boi2 double mutant cells become large and round or lyse with buds, displaying defects in bud formation and in the maintenance of cell polarity (1). Both Boi1p and Boi2p contain SH3, pleckstrin homology (PH), and proline-rich domains. (2, 1) Several structure/function and genetic analysis experiments have been done to determine which domains are important for interactions with other proteins involved in these processes. (2, 1, 6, 7) These studies showed that the Boi proteins interact physically and/or genetically with Bem1p, another SH3 domain protein, as well as three Rho-type GTPases: Cdc42p, Rho3p and the Rho3-related Rho4p (2, 1, 6, 7).

Rho3p/Rho4p interactions: Overexpression of either Rho3p or Rho4p suppresses the synthetic lethality of the boi1 boi2 mutations (2, 1).

Bem1p interactions: Two-hybrid analysis revealed that the proline-rich region of the Boi proteins mediates the interaction with the second SH3 domain of Bem1p (2, 1). Expressing the Boi1 protein with mutations in the proline-rich region suppresses boi1 boi2 double mutants as well as boi1 boi2 bem1 triple mutants (2).

Cdc42p interactions: The PH domain of the Boi proteins is necessary and sufficient for function and mediates the interaction with Cdc42p in the two-hybrid system (2). Additional two-hybrid experiments with Cdc42p point mutants suggest that the Boi proteins interact with the GTP-bound Cdc42p (2). Cells overexpressing Boi1p or Boi2p arrest as large, unbudded cells; cooverexpression of Cdc42p suppresses this defect (1, 8, 2)

Last updated: 1999-04-29 Contact SGD

References cited on this page View Complete Literature Guide for BOI1
1) Matsui Y, et al.  (1996) Yeast src homology region 3 domain-binding proteins involved in bud formation. J Cell Biol 133(4):865-78
2) Bender L, et al.  (1996) Associations among PH and SH3 domain-containing proteins and Rho-type GTPases in Yeast. J Cell Biol 133(4):879-94
3) Hallett MA, et al.  (2002) Probing the importance and potential roles of the binding of the PH-domain protein Boi1 to acidic phospholipids. BMC Cell Biol 3():16
4) Byrne KP and Wolfe KH  (2005) The Yeast Gene Order Browser: combining curated homology and syntenic context reveals gene fate in polyploid species. Genome Res 15(10):1456-61
5) Tkach JM, et al.  (2012) Dissecting DNA damage response pathways by analysing protein localization and abundance changes during DNA replication stress. Nat Cell Biol 14(9):966-76
6) Chenevert J, et al.  (1992) A yeast gene (BEM1) necessary for cell polarization whose product contains two SH3 domains. Nature 356(6364):77-9
7) Madden K and Snyder M  (1998) Cell polarity and morphogenesis in budding yeast. Annu Rev Microbiol 52():687-744
8) Akada R, et al.  (1997) Screening and identification of yeast sequences that cause growth inhibition when overexpressed. Mol Gen Genet 254(3):267-74