Genomic sequencing has made it clear that a large fraction of the genes specifying the core biological functions are shared by all eukaryotes. Knowledge of the biological role of such shared proteins in one organism can often be transferred to other organisms. The goal of the Gene Ontology Consortium is to produce a dynamic, controlled vocabulary that can be applied to all eukaryotes even as knowledge of gene and protein roles in cells is accumulating and changing. To this end, three independent ontologies accessible on the World-Wide Web (http://www.geneontology.org) are being constructed: biological process, molecular function and cellular component.

/pdf/gene-ontology-tool-for-the-unification-of-biology-ppsktrcye3.pdf

Gene Ontology: tool for the unification of biology

Recent successes illustrate the role of mass spectrometry-based proteomics as an indispensable tool for molecular and cellular biology and for the emerging field of systems biology. These include the study of protein-protein interactions via affinity-based isolations on a small and proteome-wide scale, the mapping of numerous organelles, the concurrent description of the malaria parasite genome and proteome, and the generation of quantitative protein profiles from diverse species. The ability of mass spectrometry to identify and, increasingly, to precisely quantify thousands of proteins from complex samples can be expected to impact broadly on biology and medicine.

Mass spectrometry-based proteomics

The p21 Cdk-interacting protein Cip1 is a potent inhibitor of G1 cyclin-dependent kinases

In certain aspects, the invention relates to methods for identifying compounds which modulate Akt activity mediated by the rictor-mTOR complex and methods for treating or preventing a disorder that is associated with aberrant Akt activity.

http://science.sciencemag.org/content/sci/307/5712/1098.full.pdf

Phosphorylation and regulation of Akt/PKB by the rictor-mTOR complex

Protein kinase C, an enzyme that is activated by the receptor-mediated hydrolysis of inositol phospholipids, relays information in the form of a variety of extracellular signals across the membrane to regulate many Ca2+-dependent processes. At an early phase of cellular responses, the enzyme appears to have a dual effect, providing positive forward as well as negative feedback controls over various steps of its own and other signaling pathways, such as the receptors that are coupled to inositol phospholipid hydrolysis and those of some growth factors. In biological systems, a positive signal is frequently followed by immediate negative feedback regulation. Such a novel role of this protein kinase system seems to give a logical basis for clarifying the biochemical mechanism of signal transduction, and to add a new dimension essential to our understanding of cell-to-cell communication.

https://science.sciencemag.org/content/sci/233/4761/305.full.pdf

Studies and perspectives of protein kinase C

The rod-shaped fission yeast Schizosaccharomyces pombe, which undergoes cycles of monopolar-to-bipolar tip growth, is an attractive organism for studying cell-cycle regulation of polarity establishment. While previous research has described factors mediating this process from interphase cell tips, we found that division site signaling also impacts the re-establishment of bipolar cell growth in the ensuing cell cycle. Complete loss or targeted disruption of the non-essential cytokinesis protein Fic1 at the division site, but not at interphase cell tips, resulted in many cells failing to grow at new ends created by cell division. This appeared due to faulty disassembly and abnormal persistence of the cell division machinery at new ends of fic1Δ cells. Moreover, additional mutants defective in the final stages of cytokinesis exhibited analogous growth polarity defects, supporting that robust completion of cell division contributes to new end-growth competency. To test this model, we genetically manipulated S. pombe cells to undergo new end take-off immediately after cell division. Intriguingly, such cells elongated constitutively at new ends unless cytokinesis was perturbed. Thus, cell division imposes constraints that partially override positive controls on growth. We posit that such constraints facilitate invasive fungal growth, as cytokinesis mutants displaying bipolar growth defects formed numerous pseudohyphae. Collectively, these data highlight a role for previous cell cycles in defining a cell's capacity to polarize at specific sites, and they additionally provide insight into how a unicellular yeast can transition into a quasi-multicellular state.

/pdf/cytokinesis-based-constraints-on-polarized-cell-growth-in-3ncwlef79m.pdf

Cytokinesis-Based Constraints on Polarized Cell Growth in Fission Yeast

The periodicity of CDKs (cyclin-dependent kinases) regulates most cell cycle transitions including cytokinesis. High Cdk1 activity promotes cytoskeletal rearrangements necessary for cell division while at the same time ensuring that cytokinesis does not begin before the separation of sister chromatids during anaphase. The conserved Cdc14 (cell division cycle 14)-family of phosphatases reverses Cdk phosphorylation events and therefore Cdc14 phosphatases promote the process of cytokinesis. Here, we review the elucidated roles of Cdc14 phosphatases in cytokinesis and the current outstanding questions regarding their function in this process.

The role of Cdc14 phosphatases in the control of cell division.

As cells grow, move, and divide, they must reorganize and rearrange their membranes and cytoskeleton. The F-BAR protein family links cellular membranes with actin cytoskeletal rearrangements in processes including endocytosis, cytokinesis, and cell motility. Here we review emerging information on mechanisms of F-BAR domain oligomerization and membrane binding, and how these activities are coordinated with additional domains to accomplish scaffolding and signaling functions.

https://www.tandfonline.com/doi/pdf/10.1080/15384101.2016.1190893

Linking up at the BAR: Oligomerization and F-BAR protein function

Cytokinesis, the terminal event in the canonical cell cycle, physically separates daughter cells following mitosis. For cleavage to occur in many eukaryotes, a cytokinetic ring must assemble and constrict between divided genomes. Although dozens of different molecules localize to and participate within the cytokinetic ring, the core machinery comprises linear actin filaments. Accordingly, formins, which nucleate and elongate F-actin (filamentous actin) for the cytokinetic ring, are required for cytokinesis in diverse species. In the present article, we discuss specific modes of formin-based actin regulation during cell division and highlight emerging mechanisms and questions on this topic.

/pdf/formin-based-control-of-the-actin-cytoskeleton-during-2vps91rgok.pdf

Formin-based control of the actin cytoskeleton during cytokinesis

https://uknowledge.uky.edu/cgi/viewcontent.cgi?article=1078&context=biochem_facpub

Kathleen L. Gould

Papers

Cytokinesis-Based Constraints on Polarized Cell Growth in Fission Yeast

The role of Cdc14 phosphatases in the control of cell division.

Linking up at the BAR: Oligomerization and F-BAR protein function

Formin-based control of the actin cytoskeleton during cytokinesis

The Tubulation Activity of a Fission Yeast F-BAR Protein Is Dispensable for Its Function in Cytokinesis