Sec66-Dependent Regulation of Yeast Spindle-Pole Body Duplication Through Pom152.
In closed mitotic systems such as Saccharomyces cerevisiae, the nuclear envelope (NE) does not break down during mitosis, so microtubule-organizing centers such as the spindle-pole body (SPB) must be inserted into the NE to facilitate bipolar spindle formation and chromosome segregation. The mechanism of SPB insertion has been linked to NE insertion of nuclear pore complexes (NPCs) through a series of genetic and physical interactions between NPCs and SPB components. To identify new genes involved in SPB duplication and NE insertion, we carried out genome-wide screens for suppressors of deletion alleles of SPB components, including Mps3 and Mps2. In addition to the nucleoporins POM152 and POM34, we found that elimination of SEC66/SEC71/KAR7 suppressed lethality of cells lacking MPS2 or MPS3. Sec66 is a nonessential subunit of the Sec63 complex that functions together with the Sec61 complex in import of proteins into the endoplasmic reticulum (ER). Cells lacking Sec66 have reduced levels of Pom152 protein but not Pom34 or Ndc1, a shared component of the NPC and SPB. The fact that Sec66 but not other subunits of the ER translocon bypass deletion mutants in SPB genes suggests a specific role for Sec66 in the control of Pom152 levels. Based on the observation that sec66∆ does not affect the distribution of Ndc1 on the NE or Ndc1 binding to the SPB, we propose that Sec66-mediated regulation of Pom152 plays an NPC-independent role in the control of SPB duplication.
Stowers Institute for Medical Research, Kansas City, Missouri 64110.
Santharam S
SS
Katta
Stowers Institute for Medical Research, Kansas City, Missouri 64110.
Jingjing
J
Chen
Stowers Institute for Medical Research, Kansas City, Missouri 64110.
Jennifer M
JM
Gardner
Stowers Institute for Medical Research, Kansas City, Missouri 64110.
Jennifer M
JM
Friederichs
Stowers Institute for Medical Research, Kansas City, Missouri 64110.
Sarah E
SE
Smith
Stowers Institute for Medical Research, Kansas City, Missouri 64110.
Madelaine
M
Gogol
Stowers Institute for Medical Research, Kansas City, Missouri 64110.
Jay R
JR
Unruh
Stowers Institute for Medical Research, Kansas City, Missouri 64110.
Brian D
BD
Slaughter
Stowers Institute for Medical Research, Kansas City, Missouri 64110 Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas 66160 slj@stowers.org.
Sue L
SL
Jaspersen
D015825:Chromosomes, Fungal / Q000502:physiology; D008540:Meiosis; D008562:Membrane Glycoproteins / Q000502:physiology*; D008565:Membrane Proteins / Q000502:physiology; D008938:Mitosis; D009685:Nuclear Envelope / Q000502:physiology*; D009687:Nuclear Proteins / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology*; D008941:Spindle Apparatus / Q000502:physiology*; D013489:Suppression, Genetic
D008562:Membrane Glycoproteins; D008565:Membrane Proteins; C471174:Mps3 protein, S cerevisiae; D009687:Nuclear Proteins; C086449:POM152 protein, S cerevisiae; C084842:SEC66 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins
Mps3; Nbp1; Pom152; Sec66/Sec71/Kar7; spindle-pole body