Scp160p, a new yeast protein associated with the nuclear membrane and the endoplasmic reticulum, is necessary for maintenance of exact ploidy

Yeast. 1995 Aug;11(10):929-44. doi: 10.1002/yea.320111004.


We have cloned a new gene, SCP160, from Saccharomyces cerevisiae, the deduced amino acid sequence of which does not exhibit overall similarity to any known yeast protein. A weak resemblance between the C-terminal part of the Scp160 protein and regulatory subunits of cAMP-dependent protein kinases from eukaryotes as well as the pstB protein of Escherichia coli was observed. The SCP160 gene resides on the left arm of chromosome X and codes for a polypeptide of molecular weight around 160 kDa. By immunofluorescence microscopy the Scp160 protein appears to be localized to the nuclear envelope and to the endoplasmic reticulum (ER). However, no signal sequence or membrane-spanning region exists, suggesting that the Scp160 protein is attached to the cytoplasmic surface of the ER-nuclear envelope membranes. Disruption of the SCP160 gene is not lethal but results in cells of decreased viability, abnormal morphology and increased DNA content. This phenotype is not reversible by transformation with a plasmid carrying the wild-type gene. Crosses of SCP160 deletion mutant strains among each other or with unrelated strains lead to irregular segregation of genetic markers. Taken together the data suggest that the Scp160 protein is required during cell division for faithful partitioning of the ER-nuclear envelope membranes which in S. cerevisiae enclose the duplicated chromosomes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Cell Division
  • Cloning, Molecular
  • DNA, Fungal / genetics
  • Endoplasmic Reticulum / metabolism
  • Fungal Proteins / genetics*
  • Fungal Proteins / metabolism
  • Genes, Fungal
  • Membrane Proteins / genetics*
  • Membrane Proteins / metabolism
  • Microscopy, Fluorescence
  • Molecular Sequence Data
  • Nuclear Envelope / metabolism
  • Nuclear Proteins / genetics*
  • Nuclear Proteins / metabolism
  • Phenotype
  • Ploidies*
  • RNA-Binding Proteins
  • Restriction Mapping
  • Saccharomyces cerevisiae / cytology
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins*
  • Sequence Deletion
  • Sequence Homology, Amino Acid
  • Transformation, Genetic


  • DNA, Fungal
  • Fungal Proteins
  • Membrane Proteins
  • Nuclear Proteins
  • RNA-Binding Proteins
  • SCP160 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins

Associated data

  • GENBANK/X65645