MAD3/YJL013C Summary Help

Standard Name MAD3 1
Systematic Name YJL013C
Feature Type ORF, Verified
Description Subunit of spindle-assembly checkpoint complex; involved in delaying anaphase onset in cells with defects in mitotic spindle assembly; pseudosubstrate inhibitor of APC(Cdc20), the anaphase promoting complex involved in securin (Pds1p) turnover; MAD3 has a paralog, BUB1, that arose from the whole genome duplication (2, 3, 4 and see Summary Paragraph)
Name Description Mitotic Arrest-Deficient 1, 2
Chromosomal Location
ChrX:411040 to 409493 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Gene Ontology Annotations All MAD3 GO evidence and references
  View Computational GO annotations for MAD3
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 9 genes
Classical genetics
reduction of function
Large-scale survey
170 total interaction(s) for 93 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 1
  • Affinity Capture-Western: 11
  • Biochemical Activity: 1
  • Co-crystal Structure: 1
  • Co-fractionation: 1
  • Reconstituted Complex: 1
  • Two-hybrid: 12

Genetic Interactions
  • Dosage Lethality: 1
  • Negative Genetic: 73
  • Phenotypic Enhancement: 3
  • Phenotypic Suppression: 8
  • Positive Genetic: 3
  • Synthetic Growth Defect: 21
  • Synthetic Lethality: 31
  • Synthetic Rescue: 2

Expression Summary
Length (a.a.) 515
Molecular Weight (Da) 59,521
Isoelectric Point (pI) 7.83
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrX:411040 to 409493 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Last Update Coordinates: 2011-02-03 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..1548 411040..409493 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 SGDIDS000003550

MAD3 is a non-essential gene that encodes a component of the spindle checkpoint (2). The spindle checkpoint delays the onset of anaphase in cells with defects in mitotic spindle assembly or in the attachment of chromosomes to the spindle microtubules (see 5 for review; reference 6 describes defects detected by the checkpoint). The checkpoint works by inhibiting the activity of the anaphase promoting complex, thereby preventing the degradation of several cell cycle regulators (5). Like other spindle checkpoint mutants, mad3 null mutants are sensitive to benomyl and cannot delay cell division in response to spindle depolymerization (2). Mad3p localizes to the nucleus and interacts physically with the spindle checkpoint proteins Bub3p and Mad2p, and with Cdc20p, which activates the anaphase promoting complex (7, 2). Mad3p, Mad2p, and Cdc20p form a complex; Mad1p and Mad2p are required for Mad3p to bind to the complex (7). Mad3p shows sequence similarity to the protein kinase Bub1p (2), which is also involved in the spindle checkpoint (8), and to Bub1p-related protein kinases in other species (for example, see 9 and 10). The sequence similarity does not include the kinase domain of Bub1p (2). Bub1p, Bub3p, Mad1p, Mad2p, Mad3p, and the protein kinase Mps1p act in a branch of the spindle checkpoint that may prevent premature chromosome disjunction. A second branch involves Bub2p and Bfa1p, and may prevent cytokinesis prior to chromosome segregation (11, 12, 13, 14).

Last updated: 2000-03-31 Contact SGD

References cited on this page View Complete Literature Guide for MAD3
1) Li R and Murray AW  (1991) Feedback control of mitosis in budding yeast. Cell 66(3):519-31
2) Hardwick KG, et al.  (2000) MAD3 encodes a novel component of the spindle checkpoint which interacts with Bub3p, Cdc20p, and Mad2p. J Cell Biol 148(5):871-82
3) 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
4) Burton JL and Solomon MJ  (2007) Mad3p, a pseudosubstrate inhibitor of APCCdc20 in the spindle assembly checkpoint. Genes Dev 21(6):655-67
5) Hardwick KG  (1998) The spindle checkpoint. Trends Genet 14(1):1-4
6) Hardwick KG, et al.  (1999) Lesions in many different spindle components activate the spindle checkpoint in the budding yeast Saccharomyces cerevisiae. Genetics 152(2):509-18
7) Hwang LH, et al.  (1998) Budding yeast Cdc20: a target of the spindle checkpoint. Science 279(5353):1041-4
8) Roberts BT, et al.  (1994) The Saccharomyces cerevisiae checkpoint gene BUB1 encodes a novel protein kinase. Mol Cell Biol 14(12):8282-91
9) Bernard P, et al.  (1998) Fission yeast bub1 is a mitotic centromere protein essential for the spindle checkpoint and the preservation of correct ploidy through mitosis. J Cell Biol 143(7):1775-87
10) Taylor SS and McKeon F  (1997) Kinetochore localization of murine Bub1 is required for normal mitotic timing and checkpoint response to spindle damage. Cell 89(5):727-35
11) Alexandru G, et al.  (1999) Sister chromatid separation and chromosome re-duplication are regulated by different mechanisms in response to spindle damage. EMBO J 18(10):2707-21
12) Fesquet D, et al.  (1999) A Bub2p-dependent spindle checkpoint pathway regulates the Dbf2p kinase in budding yeast. EMBO J 18(9):2424-34
13) Fraschini R, et al.  (1999) Budding yeast Bub2 is localized at spindle pole bodies and activates the mitotic checkpoint via a different pathway from Mad2. J Cell Biol 145(5):979-91
14) Li R  (1999) Bifurcation of the mitotic checkpoint pathway in budding yeast. Proc Natl Acad Sci U S A 96(9):4989-94