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FtsZ
FtsZ is a protein encoded by the ''ftsZ'' gene that assembles into a ring at the future site of bacterial cell division (also called the Z ring). FtsZ is a prokaryotic homologue of the eukaryotic protein tubulin. The initials FtsZ mean "Filamenting temperature-sensitive mutant Z." The hypothesis was that cell division mutants of '' E. coli'' would grow as filaments due to the inability of the daughter cells to separate from one another. FtsZ is found in almost all bacteria, many archaea, all chloroplasts and some mitochondria, where it is essential for cell division. FtsZ assembles the cytoskeletal scaffold of the Z ring that, along with additional proteins, constricts to divide the cell in two. History In the 1960s scientists screened for temperature sensitive mutations that blocked cell division at 42 °C. The mutant cells divided normally at 30°, but failed to divide at 42°. Continued growth without division produced long filamentous cells (Filamenting temperature s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FtsZ Filaments
FtsZ is a protein encoded by the ''ftsZ'' gene that assembles into a ring at the future site of bacterial cell division (also called the Z ring). FtsZ is a prokaryotic homologue of the eukaryotic protein tubulin. The initials FtsZ mean "Filamenting temperature-sensitive mutant Z." The hypothesis was that cell division mutants of ''E. coli'' would grow as filaments due to the inability of the daughter cells to separate from one another. FtsZ is found in almost all bacteria, many archaea, all chloroplasts and some mitochondria, where it is essential for cell division. FtsZ assembles the cytoskeletal scaffold of the Z ring that, along with additional proteins, constricts to divide the cell in two. History In the 1960s scientists screened for temperature sensitive mutations that blocked cell division at 42 °C. The mutant cells divided normally at 30°, but failed to divide at 42°. Continued growth without division produced long filamentous cells (Filamenting temperature se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FtsZ2
FtsZ is a protein encoded by the ''ftsZ'' gene that assembles into a ring at the future site of bacterial cell division (also called the Z ring). FtsZ is a prokaryotic homologue of the eukaryotic protein tubulin. The initials FtsZ mean "Filamenting temperature-sensitive mutant Z." The hypothesis was that cell division mutants of ''E. coli'' would grow as filaments due to the inability of the daughter cells to separate from one another. FtsZ is found in almost all bacteria, many archaea, all chloroplasts and some mitochondria, where it is essential for cell division. FtsZ assembles the cytoskeletal scaffold of the Z ring that, along with additional proteins, constricts to divide the cell in two. History In the 1960s scientists screened for temperature sensitive mutations that blocked cell division at 42 °C. The mutant cells divided normally at 30°, but failed to divide at 42°. Continued growth without division produced long filamentous cells (Filamenting temperature se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FtsZ1
FtsZ is a protein encoded by the ''ftsZ'' gene that assembles into a ring at the future site of bacterial cell division (also called the Z ring). FtsZ is a prokaryotic homologue of the eukaryotic protein tubulin. The initials FtsZ mean "Filamenting temperature-sensitive mutant Z." The hypothesis was that cell division mutants of ''E. coli'' would grow as filaments due to the inability of the daughter cells to separate from one another. FtsZ is found in almost all bacteria, many archaea, all chloroplasts and some mitochondria, where it is essential for cell division. FtsZ assembles the cytoskeletal scaffold of the Z ring that, along with additional proteins, constricts to divide the cell in two. History In the 1960s scientists screened for temperature sensitive mutations that blocked cell division at 42 °C. The mutant cells divided normally at 30°, but failed to divide at 42°. Continued growth without division produced long filamentous cells (Filamenting temperature se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FtsA
FtsA is a bacterial protein that is related to actin by overall structural similarity and in its ATP binding pocket. Along with other bacterial actin homologs such as MreB, ParM, and MamK, these proteins suggest that eukaryotic actin has a common ancestry. Like the other bacterial actins, FtsA binds ATP and can form actin-like filaments. The FtsA-FtsA interface has been defined by structural as well as genetic analysis. Although present in many diverse Gram-positive and Gram-negative species, FtsA is absent in actinobacteria and cyanobacteria. FtsA also is structurally similar to PilM, a type IV pilus ATPase. Function FtsA is required for proper cytokinesis in bacteria such as ''Escherichia coli'', ''Caulobacter crescentus'', and ''Bacillus subtilis''. Originally isolated in a screen for ''E. coli'' cells that could divide at 30˚C but not at 40˚C, FtsA stands for "filamentous temperature sensitive A". Many thermosensitive alleles of ''E. coli ftsA'' exist, and all map in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tubulin
Tubulin in molecular biology can refer either to the tubulin protein superfamily of globular proteins, or one of the member proteins of that superfamily. α- and β-tubulins polymerize into microtubules, a major component of the eukaryotic cytoskeleton. Microtubules function in many essential cellular processes, including mitosis. Tubulin-binding drugs kill cancerous cells by inhibiting microtubule dynamics, which are required for DNA segregation and therefore cell division. In eukaryotes, there are six members of the tubulin superfamily, although not all are present in all species.Turk E, Wills AA, Kwon T, Sedzinski J, Wallingford JB, Stearns "Zeta-Tubulin Is a Member of a Conserved Tubulin Module and Is a Component of the Centriolar Basal Foot in Multiciliated Cells"Current Biology (2015) 25:2177-2183. Both α and β tubulins have a mass of around 50 kDa and are thus in a similar range compared to actin (with a mass of ~42 kDa). In contrast, tubulin polymers (microtubules) te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Treadmilling
In molecular biology, treadmilling is a phenomenon observed within protein filaments of the cytoskeletons of many cells, especially in actin filaments and microtubules. It occurs when one end of a filament grows in length while the other end shrinks, resulting in a section of filament seemingly "moving" across a stratum or the cytosol. This is due to the constant removal of the protein subunits from these filaments at one end of the filament, while protein subunits are constantly added at the other end. Treadmilling was discovered by Wegner, who defined the thermodynamic and kinetic constraints. Wegner recognized that: “The equilibrium constant (K) for association of a monomer with a polymer is the same at both ends, since the addition of a monomer to each end leads to the same polymer.”; a simple reversible polymer can’t treadmill; ATP hydrolysis is required. GTP is hydrolyzed for microtubule treadmilling. Detailed process Dynamics of the filament The cytoskeleton ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filamentation
Filamentation is the anomalous growth of certain bacteria, such as ''Escherichia coli'', in which cells continue to elongate but do not divide (no septa formation). The cells that result from elongation without division have multiple chromosomal copies. In the absence of antibiotics or other stressors, filamentation occurs at a low frequency in bacterial populations (4–8% short filaments and 0–5% long filaments in 1- to 8-hour cultures). The increased cell length can protect bacteria from protozoan predation and neutrophil phagocytosis by making ingestion of cells more difficult. Filamentation is also thought to protect bacteria from antibiotics, and is associated with other aspects of bacterial virulence such as biofilm formation. The number and length of filaments within a bacterial population increases when the bacteria are exposed to different physical, chemical and biological agents (e.g. UV light, DNA synthesis-inhibiting antibiotics, bacteriophages). This is termed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filamentation 1
Filamentation is the anomalous growth of certain bacteria, such as ''Escherichia coli'', in which cells continue to elongate but do not divide (no septa formation). The cells that result from elongation without division have multiple chromosomal copies. In the absence of antibiotics or other stressors, filamentation occurs at a low frequency in bacterial populations (4–8% short filaments and 0–5% long filaments in 1- to 8-hour cultures). The increased cell length can protect bacteria from protozoan predation and neutrophil phagocytosis by making ingestion of cells more difficult. Filamentation is also thought to protect bacteria from antibiotics, and is associated with other aspects of bacterial virulence such as biofilm formation. The number and length of filaments within a bacterial population increases when the bacteria are exposed to different physical, chemical and biological agents (e.g. UV light, DNA synthesis-inhibiting antibiotics, bacteriophages). This is termed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloroplast
A chloroplast () is a type of membrane-bound organelle known as a plastid that conducts photosynthesis mostly in plant and algal cells. The photosynthetic pigment chlorophyll captures the energy from sunlight, converts it, and stores it in the energy-storage molecules ATP and NADPH while freeing oxygen from water in the cells. The ATP and NADPH is then used to make organic molecules from carbon dioxide in a process known as the Calvin cycle. Chloroplasts carry out a number of other functions, including fatty acid synthesis, amino acid synthesis, and the immune response in plants. The number of chloroplasts per cell varies from one, in unicellular algae, up to 100 in plants like ''Arabidopsis'' and wheat. A chloroplast is characterized by its two membranes and a high concentration of chlorophyll. Other plastid types, such as the leucoplast and the chromoplast, contain little chlorophyll and do not carry out photosynthesis. Chloroplasts are highly dynamic—they circulat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Actin
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. An actin protein is the monomeric subunit of two types of filaments in cells: microfilaments, one of the three major components of the cytoskeleton, and thin filaments, part of the contractile apparatus in muscle cells. It can be present as either a free monomer called G-actin (globular) or as part of a linear polymer microfilament called F-actin (filamentous), both of which are essential for such important cellular functions as the mobility and contraction of cells during cell division. Actin participates in many important cellular processes, including muscle contraction, cell motility, cell division and cytokinesis, vesicle and organelle movement, cell sign ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Segrosome
Segrosomes are protein complexes that ensure accurate segregation (partitioning) of plasmids or chromosomes during bacterial cell division. Just as higher forms of life have evolved a complex mitotic apparatus to partition duplicated DNA during cell division, bacteria require a specialized apparatus to partition their duplicated DNA. In bacteria, segrosomes perform the function similar to that performed by mitotic spindle. Therefore, segrosomes can be thought of as minimalist spindles. Segrosomes are usually composed of three basic components- the DNA (plasmid or chromosome) that needs to be segregated into daughter cells, a motor protein that provides the necessary physical forces for accomplishing the segregation and a DNA binding protein that connects the DNA and the motor protein, to form the complete segrosome complex. Motor proteins present in bacterial segrosomal complexes The majority of motor proteins participating in plasmid segrosomes are Walker-type or ParM type ATPas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joe Lutkenhaus
Joe Lutkenhaus is a professor at the University of Kansas Medical Center. He received a B.S. in organic chemistry from Iowa state University and then a PhD in biochemistry for the University of California, Los Angeles. Following his PhD, Lutkenhaus pursued his postdoctoral studies with William Donachie at the University of Edinburgh and then continued at the University of Connecticut Health Science center. In 2002, Lutkenhaus became a fellow of the American Academy of Microbiology. Lutkenhaus discovered, among other things, that the FtsZ protein forms a ring around the division plane in bacteria and is thus a key factor in bacterial cell division. Honors *Member of the American Academy of Microbiology *2012 Louisa Gross Horwitz Prize *2014 Member of the National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the Nat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
