MAD1/YGL086W Summary Help

Standard Name MAD1 1
Systematic Name YGL086W
Feature Type ORF, Verified
Description Coiled-coil protein involved in spindle-assembly checkpoint; required for inhibition of karyopherin/importin Pse1p (aka Kap121p) upon spindle assembly checkpoint arrest; phosphorylated by Mps1p upon checkpoint activation which leads to inhibition of anaphase promoting complex activity; forms a complex with Mad2p; gene dosage imbalance between MAD1 and MAD2 leads to chromosome instability (2, 3, 4, 5 and see Summary Paragraph)
Name Description Mitotic Arrest-Deficient 1, 3
Chromosomal Location
ChrVII:347119 to 349368 | ORF Map | GBrowse
Gene Ontology Annotations All MAD1 GO evidence and references
  View Computational GO annotations for MAD1
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 3 genes
Classical genetics
Large-scale survey
532 total interaction(s) for 305 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 7
  • Affinity Capture-RNA: 1
  • Affinity Capture-Western: 12
  • Biochemical Activity: 1
  • Co-fractionation: 1
  • Co-localization: 4
  • Co-purification: 1
  • Reconstituted Complex: 3
  • Two-hybrid: 40

Genetic Interactions
  • Negative Genetic: 158
  • Phenotypic Enhancement: 11
  • Phenotypic Suppression: 5
  • Positive Genetic: 9
  • Synthetic Growth Defect: 55
  • Synthetic Lethality: 220
  • Synthetic Rescue: 4

Expression Summary
Length (a.a.) 749
Molecular Weight (Da) 87,651
Isoelectric Point (pI) 5.18
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrVII:347119 to 349368 | ORF Map | GBrowse
Last Update Coordinates: 2011-02-03 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..2250 347119..349368 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 SGDIDS000003054

MAD1 is a non-essential gene that encodes a component of the spindle checkpoint (1, 3). The spindle checkpoint delays the onset of anaphase in cells with defects in mitotic spindle assembly or in the attachment o f chromosomes to the spindle microtubules (see 6 for review; reference 7 describes defects detected by the c heckpoint). The checkpoint works by inhibiting the activity of the anaphase promoting complex, thereby preventing the degradation of several cell cycl e regulators (6). Like other spindle checkpoint mutants, mad1 loss-of-function mutants are sensitive to benomyl and cannot delay cell division in response to spindle depolymerization (1, 3). Mad1p becomes hyperphosphorylated upon spindle depolymerization (3). The essential protein kinase Msp 1p is involved in the spindle checkpoint, and appears to phosphorylate Mad1p (2,8). Mad1p forms a tight complex with another spindle checkpoint protein, Mad2p, throughout the cell cycle (9). Mad1p interacts with Cdc20p, which activates the anaphase promoting complex, in the two-hybrid system, and the presence of Mad1p is required for Mad2 p and Mad3p to interact with Cdc20p (10). Bub1p, Bub3p, Mad1p, Mad2p, Mad3p, and Mps1p act in a branch of the spindle checkpoint pathway 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). Homologs of Mad1p act in the spindle checkpoint in Xenopus (Xmad1; 15) and human (MAD1L1; 16).

Last updated: 2005-07-01 Contact SGD

References cited on this page View Complete Literature Guide for MAD1
1) Li R and Murray AW  (1991) Feedback control of mitosis in budding yeast. Cell 66(3):519-31
2) Hardwick KG, et al.  (1996) Activation of the budding yeast spindle assembly checkpoint without mitotic spindle disruption. Science 273(5277):953-6
3) Hardwick KG and Murray AW  (1995) Mad1p, a phosphoprotein component of the spindle assembly checkpoint in budding yeast. J Cell Biol 131(3):709-20
4) Zhu J, et al.  (2012) Karyotypic determinants of chromosome instability in aneuploid budding yeast. PLoS Genet 8(5):e1002719
5) Cairo LV, et al.  (2013) Mitosis-specific regulation of nuclear transport by the spindle assembly checkpoint protein Mad1p. Mol Cell 49(1):109-20
6) Hardwick KG  (1998) The spindle checkpoint. Trends Genet 14(1):1-4
7) 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
8) Weiss E and Winey M  (1996) The Saccharomyces cerevisiae spindle pole body duplication gene MPS1 is part of a mitotic checkpoint. J Cell Biol 132(1-2):111-23
9) Chen RH, et al.  (1999) The spindle checkpoint of budding yeast depends on a tight complex between the Mad1 and Mad2 proteins. Mol Biol Cell 10(8):2607-18
10) Hwang LH, et al.  (1998) Budding yeast Cdc20: a target of the spindle checkpoint. Science 279(5353):1041-4
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
15) Chen RH, et al.  (1998) Spindle checkpoint protein Xmad1 recruits Xmad2 to unattached kinetochores. J Cell Biol 143(2):283-95
16) Jin DY, et al.  (1998) Human T cell leukemia virus type 1 oncoprotein Tax targets the human mitotic checkpoint protein MAD1. Cell 93(1):81-91