PAC2/YER007W Summary Help

Standard Name PAC2 1
Systematic Name YER007W
Feature Type ORF, Verified
Description Microtubule effector required for tubulin heterodimer formation; binds alpha-tubulin, required for normal microtubule function, null mutant exhibits cold-sensitive microtubules and sensitivity to benomyl (1, 2, 3, 4 and see Summary Paragraph)
Name Description Perish in the Absence of Cin8p 5
Chromosomal Location
ChrV:164527 to 166083 | ORF Map | GBrowse
Gene Ontology Annotations All PAC2 GO evidence and references
  View Computational GO annotations for PAC2
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 1 genes
Classical genetics
reduction of function
Large-scale survey
85 total interaction(s) for 53 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 5
  • Affinity Capture-RNA: 1
  • Affinity Capture-Western: 5
  • Two-hybrid: 1

Genetic Interactions
  • Dosage Lethality: 2
  • Dosage Rescue: 2
  • Negative Genetic: 19
  • Phenotypic Enhancement: 2
  • Positive Genetic: 4
  • Synthetic Growth Defect: 17
  • Synthetic Lethality: 27

Expression Summary
Length (a.a.) 518
Molecular Weight (Da) 59,257
Isoelectric Point (pI) 8.91
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrV:164527 to 166083 | ORF Map | GBrowse
Last Update Coordinates: 2011-02-03 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..1557 164527..166083 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 SGDIDS000000809

Microtubules are conserved cytoskeletal elements that form by the polymerization of alpha- and beta-tubulin heterodimers. The formation of polymerization-competent tubulin heterodimers requires that alpha-tubulin and beta-tubulin are properly folded. Specific cofactors are required for the post-chaperonin folding of alpha- and beta-tubulin in vitro and homologs of these cofactors have been found in numerous organisms, including S.cerevisiae (reviewed in 6).

In S.cerevisiae, PAC2 is a non-essential gene that is homologous to mammalian cofactor E (7, 1, 4). Consistent with the in vitro studies, genetic analyses of PAC2 demonstrate that Pac2p acts downstream of Alf1p/cofactor B in alpha-tubulin folding, and in parallel with Rbl2p/cofactor A and Cin1p/cofactor D, in beta-tubulin folding (7, 1, 4, 2). Similar to the other yeast cofactors, pac2 null mutants are super-sensitive to benomyl, a microtubule depolymerizing drug (7). Overexpression of Cin1p can suppress the benomyl sensitivity of pac2 null mutants (1), and Cin1p and Pac2p have been shown to interact in vivo (2). Pac2p physically interacts with alpha-tubulin (4, 8), likely mediated by its single CLIP-170 domain (4, 1), found in several microtubule-associated proteins.

The PAC2 (Perish in the Absence of CIN8) gene was isolated in a genetic screen for mutants that were synthetically lethal with the mitotic kinesin, Cin8p (5).

Last updated: 2003-08-28 Contact SGD

References cited on this page View Complete Literature Guide for PAC2
1) Hoyt MA, et al.  (1997) Saccharomyces cerevisiae PAC2 functions with CIN1, 2 and 4 in a pathway leading to normal microtubule stability. Genetics 146(3):849-57
2) Fleming JA, et al.  (2000) Function of tubulin binding proteins in vivo. Genetics 156(1):69-80
3) Vega LR, et al.  (1998) An alpha-tubulin mutant destabilizes the heterodimer: phenotypic consequences and interactions with tubulin-binding proteins. Mol Biol Cell 9(9):2349-60
4) Feierbach B, et al.  (1999) Alf1p, a CLIP-170 domain-containing protein, is functionally and physically associated with alpha-tubulin. J Cell Biol 144(1):113-24
5) Geiser JR, et al.  (1997) Saccharomyces cerevisiae genes required in the absence of the CIN8-encoded spindle motor act in functionally diverse mitotic pathways. Mol Biol Cell 8(6):1035-50
6) Lopez-Fanarraga M, et al.  (2001) Review: postchaperonin tubulin folding cofactors and their role in microtubule dynamics. J Struct Biol 135(2):219-29
7) Tian G, et al.  (1997) Tubulin subunits exist in an activated conformational state generated and maintained by protein cofactors. J Cell Biol 138(4):821-32
8) Archer JE, et al.  (1998) Formation and function of the Rbl2p-beta-tubulin complex. Mol Cell Biol 18(3):1757-62