The CWI Pathway: A Versatile Toolbox to Arrest Cell-Cycle Progression.

Cell-signaling pathways are essential for cells to respond and adapt to changes in their environmental conditions. The cell-wall integrity (CWI) pathway of is activated by environmental stresses, compounds, and morphogenetic processes that compromise the cell wall, orchestrating the appropriate cellular response to cope with these adverse conditions. During cell-cycle progression, the CWI pathway is activated in periods of polarized growth, such as budding or cytokinesis, regulating cell-wall biosynthesis and the actin cytoskeleton.

An Attachment-Independent Biochemical Timer of the Spindle Assembly Checkpoint.

The spindle assembly checkpoint (SAC) generates a diffusible protein complex that prevents anaphase until all chromosomes are properly attached to spindle microtubules. A key step in SAC initiation is the recruitment of MAD1 to kinetochores, which is generally thought to be governed by the microtubule-kinetochore (MT-KT) attachment status. However, we demonstrate that the recruitment of MAD1 via BUB1, a conserved kinetochore receptor, is not affected by MT-KT interactions in human cells.

Molecular basis of the functional distinction between Cln1 and Cln2 cyclins.

Cln1 and Cln2 are very similar but not identical cyclins. In this work, we tried to describe the molecular basis of the functional distinction between Cln1 and Cln2. We constructed chimeric cyclins containing different fragments of Cln1 and Cln2 and performed several functional analysis that make it possible to distinguish between Cln1 or Cln2.

Regulation of cell cycle transcription factor Swi5 by karyopherin Msn5.

Inactivation of S. cerevisiae β-karyopherin Msn5 causes hypersensitivity to the overexpression of mitotic cyclin Clb2 and aggravates growth defects of many mutant strains in mitotic exit, suggesting a connection between Msn5 and mitotic exit. We determined that Msn5 controlled subcellular localization of the mitotic exit transcription factor Swi5, since it was required for Swi5 nuclear export.

Targeting and membrane insertion into the endoplasmic reticulum membrane of Saccharomyces cerevisiae essential protein Rot1.

Rot1 is an essential yeast protein that has been related to cell wall biosynthesis, actin cytoskeleton dynamics and protein folding. Rot1 is an N-glycosylated protein anchored to the nuclear envelope-endoplasmic reticulum (ER) membrane by a transmembrane domain at its C-terminal end. Rot1 is translocated to the ER by a post-translational mechanism.

Yeast karyopherin Kap95 is required for cell cycle progression at Start.

Background: The control of the subcellular localization of cell cycle regulators has emerged as a crucial mechanism in cell division regulation. The active transport of proteins between the nucleus and the cytoplasm is mediated by the transport receptors of the beta-karyopherin family. In this work we characterized the terminal phenotype of a mutant strain in beta-karyopherin Kap95, a component of the classical nuclear import pathway.

Yeast karyopherins Kap123 and Kap95 are related to the function of the cell integrity pathway.

The characterization of mutant strains in the gene encoding karyopherin Kap123 has revealed several morphogenetic defects. Inactivation of KAP123 caused alterations in the actin cytoskeleton, resulting in hyperpolarization and resistance to the actin polymerization inhibitor latrunculin B. In fact, the level of actin filaments is increased in kap123 mutant cells.