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Michael Tibbetts is a Professor of Biology at Bard College, Annandale-on-Hudson, New York, 12504.
B.S., Southeastern Massachusetts University; Ph.D., Wesleyan University. Teaching assistant, Peterson Fellowship, Wesleyan University. Adjunct lecturer, postdoctoral fellow, University of Michigan. Member of Sigma Xi, Genetics Society of America, American Society of Microbiology. Professional interests: cellular events that lead to appropriate spatial organization of subcellular material. Faculty, Bard Center for Environmental Policy. (1992– ) Associate Professor of Biology.
Cytoskeletal dynamics are key to issues like the appropriate spatial organization of subcellular material and cell shape changes. In the budding yeast Saccharomyces cerevisiae, actin filaments are the major structural component of the cytoskeleton. Profilin is an actin monomer binding protein that has been implicated in the control of actin polymerization and signal transduction; perhaps linking the two.
With several of his students, he has been attempting to characterize the PTM1 gene and its protein product at the molecular and cellular level. Thus far they have discovered that yeast cells in which the PTM1 gene has been removed appear normal under all conditions tested. They have also found another gene, PTM2, with a predicted amino acid sequence strikingly similar to that of PTM1, suggesting functional redundancy. It turns out that cells lacking both PTM1 & PTM2 are also indistinguishable from cells containing both genes.
While continuing to explore the link between profilin, PTM1 and PTM2, he has also begun performing genetic screens to identify genes that interact with PTM1 and/or PTM2. In addition to the molecular genetic approach, the lab is also using biochemical and cell biological approaches to look at the protein products of these two genes.
Schizosaccharomyces pombe, also called "fission yeast", is a species of yeast used in traditional brewing and as a model organism in molecular and cell biology. It is a unicellular eukaryote, whose cells are rod-shaped. Cells typically measure 3 to 4 micrometres in diameter and 7 to 14 micrometres in length. Its genome, which is approximately 14.1 million base pairs, is estimated to contain 4,970 protein-coding genes and at least 450 non-coding RNAs.
Microfilaments, also called actin filaments, are protein filaments in the cytoplasm of eukaryotic cells that form part of the cytoskeleton. They are primarily composed of polymers of actin, but are modified by and interact with numerous other proteins in the cell. Microfilaments are usually about 7 nm in diameter and made up of two strands of actin. Microfilament functions include cytokinesis, amoeboid movement, cell motility, changes in cell shape, endocytosis and exocytosis, cell contractility, and mechanical stability. Microfilaments are flexible and relatively strong, resisting buckling by multi-piconewton compressive forces and filament fracture by nanonewton tensile forces. In inducing cell motility, one end of the actin filament elongates while the other end contracts, presumably by myosin II molecular motors. Additionally, they function as part of actomyosin-driven contractile molecular motors, wherein the thin filaments serve as tensile platforms for myosin's ATP-dependent pulling action in muscle contraction and pseudopod advancement. Microfilaments have a tough, flexible framework which helps the cell in movement.
Molecular genetics is a sub-field of biology that addresses how differences in the structures or expression of DNA molecules manifests as variation among organisms. Molecular genetics often applies an "investigative approach" to determine the structure and/or function of genes in an organism's genome using genetic screens. The field of study is based on the merging of several sub-fields in biology: classical Mendelian inheritance, cellular biology, molecular biology, biochemistry, and biotechnology. Researchers search for mutations in a gene or induce mutations in a gene to link a gene sequence to a specific phenotype. Molecular genetics is a powerful methodology for linking mutations to genetic conditions that may aid the search for treatments/cures for various genetics diseases.
Biochemistry is the study of the chemical processes in living organisms. It deals with the structure and function of cellular components such as proteins, carbohydrates, lipids, nucleic acids and other biomolecules.
Actin is a family of globular multi-functional proteins that form microfilaments in the cytoskeleton, and the thin filaments in muscle fibrils. It is found in essentially all eukaryotic cells, where it may be present at a concentration of over 100 μM; its mass is roughly 42 kDa, with a diameter of 4 to 7 nm.
Two-hybrid screening is a molecular biology technique used to discover protein–protein interactions (PPIs) and protein–DNA interactions by testing for physical interactions between two proteins or a single protein and a DNA molecule, respectively.
Profilin is an actin-binding protein involved in the dynamic turnover and reconstruction of the actin cytoskeleton. It is found in all eukaryotic organisms in most cells. Profilin is important for spatially and temporally controlled growth of actin microfilaments, which is an essential process in cellular locomotion and cell shape changes. This restructuring of the actin cytoskeleton is essential for processes such as organ development, wound healing, and the hunting down of infectious intruders by cells of the immune system.
The Rho family of GTPases is a family of small signaling G proteins, and is a subfamily of the Ras superfamily. The members of the Rho GTPase family have been shown to regulate many aspects of intracellular actin dynamics, and are found in all eukaryotic kingdoms, including yeasts and some plants. Three members of the family have been studied in detail: Cdc42, Rac1, and RhoA. All G proteins are "molecular switches", and Rho proteins play a role in organelle development, cytoskeletal dynamics, cell movement, and other common cellular functions.
WAS/WASL-interacting protein (WIP) is a protein that in humans is encoded by the WIPF1 gene.
Anillin is a conserved protein implicated in cytoskeletal dynamics during cellularization and cytokinesis. The ANLN gene in humans and the scraps gene in Drosophila encode Anillin. In 1989, anillin was first isolated in embryos of Drosophila melanogaster. It was identified as an F-actin binding protein. Six years later, the anillin gene was cloned from cDNA originating from a Drosophila ovary. Staining with anti-anillin antibody showed the anillin localizes to the nucleus during interphase and to the contractile ring during cytokinesis. These observations agree with further research that found anillin in high concentrations near the cleavage furrow coinciding with RhoA, a key regulator of contractile ring formation.
mDia1 is a member of the protein family called the formins and is a Rho effector. It is the mouse version of the diaphanous homolog 1 of Drosophila. mDia1 localizes to cells' mitotic spindle and midbody, plays a role in stress fiber and filopodia formation, phagocytosis, activation of serum response factor, formation of adherens junctions, and it can act as a transcription factor. mDia1 accelerates actin nucleation and elongation by interacting with barbed ends of actin filaments. The gene encoding mDia1 is located on Chromosome 18 of Mus musculus and named Diap1.
The NAS Award in Molecular Biology is awarded by the U.S. National Academy of Sciences "for recent notable discovery in molecular biology by a young scientist who is a citizen of the United States." It has been awarded annually since its inception in 1962.
In molecular biology, the cyclase-associated protein family (CAP) is a family of highly conserved actin-binding proteins present in a wide range of organisms including yeast, flies, plants, and mammals. CAPs are multifunctional proteins that contain several structural domains. CAP is involved in species-specific signalling pathways. In Drosophila, CAP functions in Hedgehog-mediated eye development and in establishing oocyte polarity. In Dictyostelium discoideum, CAP is involved in microfilament reorganisation near the plasma membrane in a PIP2-regulated manner and is required to perpetuate the cAMP relay signal to organise fruitbody formation. In plants, CAP is involved in plant signalling pathways required for co-ordinated organ expansion. In yeast, CAP is involved in adenylate cyclase activation, as well as in vesicle trafficking and endocytosis. In both yeast and mammals, CAPs appear to be involved in recycling G-actin monomers from ADF/cofilins for subsequent rounds of filament assembly. In mammals, there are two different CAPs that share 64% amino acid identity.
Reverse genetics is a method in molecular genetics that is used to help understand the function(s) of a gene by analysing the phenotypic effects caused by genetically engineering specific nucleic acid sequences within the gene. The process proceeds in the opposite direction to forward genetic screens of classical genetics. While forward genetics seeks to find the genetic basis of a phenotype or trait, reverse genetics seeks to find what phenotypes are controlled by particular genetic sequences.
Fred Sherman was an American scientist who pioneered the use of the budding yeast Saccharomyces cerevisiae as a model for studying the genetics, molecular biology, and biochemistry of eukaryotic cells. His research encompassed broad areas of yeast biology including gene expression, protein synthesis, messenger RNA processing, bioenergetics, and mechanisms of mutagenesis. He also contributed extensively to the genetics of the opportunistic pathogen Candida albicans.
Laurence (Larry) H. Kedes was an American scientist in the fields of gene expression, genomics, and cellular differentiation. His first faculty position was at Stanford University (1970-1989) where he rose to full professor in the Department of Medicine and focused on basic molecular biology and gene expression. In 1988, the University of Southern California (USC) recruited Kedes to spearhead a campus-wide initiative to strengthen their molecular biology and genetics research programs. At USC, Kedes conceived and developed the Institute of Genetic Medicine, becoming its founding director (1989-2008) as well as the William Keck Professor (1988-2009) and Chair (1988-2002) of the Department of Biochemistry and Molecular Biology.
The Gal4 transcription factor is a positive regulator of gene expression of galactose-induced genes. This protein represents a large fungal family of transcription factors, Gal4 family, which includes over 50 members in the yeast Saccharomyces cerevisiae e.g. Oaf1, Pip2, Pdr1, Pdr3, Leu3.
Christine Guthrie is an American yeast geneticist and American Cancer Society Research Professor of Genetics at University of California San Francisco. She showed that yeast have small nuclear RNAs (snRNAs) involved in splicing pre-messenger RNA into messenger RNA in eukaryotic cells. Guthrie cloned and sequenced the genes for yeast snRNA and established the role of base pairing between the snRNAs and their target sequences at each step in the removal of an intron. She also identified proteins that formed part of the spliceosome complex with the snRNAs. Elected to the National Academy of Sciences in 1993, Guthrie edited Guide to Yeast Genetics and Molecular Biology, an influential methods series for many years.
Anthony Mahowald is a molecular genetics and cellular biologist who served as the department chair of the molecular genetics and cellular biology department at the University of Chicago. His lab focused on the Drosophila melanogaster, which is often referred to as fruit fly, specifically focusing on controlling the genetic aspect of major developmental events. His major research breakthroughs included the study of the stem cell niche, endocycles, and various types of actin.
David G. Drubin is an American biologist, academic, and researcher. He is a Distinguished Professor of Cell and Developmental Biology at the University of California, Berkeley where he holds the Ernette Comby Chair in Microbiology.