F-actin: Difference between revisions
From Proteopedia
Jump to navigationJump to search
David Canner (talk | contribs) No edit summary |
David Canner (talk | contribs) No edit summary |
||
| Line 1: | Line 1: | ||
{{STRUCTURE_2zwh| PDB=2zwh | SIZE=300| SCENE= |right|CAPTION=F-actin from rabbit complex with ADP , [[2x8f]] }} | {{STRUCTURE_2zwh| PDB=2zwh | SIZE=300| SCENE= |right|CAPTION=F-actin from rabbit complex with ADP , [[2x8f]] }} | ||
[[Image:2zwh.png|left|200px|thumb|Crystal Structure of F-actin, [[2zwh]]]]'''Filamentous actin''' ('''F-actin''') units are also referred to as [http://en.wikipedia.org/wiki/microfilament microfilaments] <ref> Microfilaments - Wikipedia, the free encyclopedia. http://en.wikipedia.org/wiki/Microfilament. Date accessed: March 16th, 2010. </ref> and are highly conserved, proteinous components found near ubiquitously in eukaryotic cytoskeletons. F-actin and other [[actin]] proteins generally have structural roles in cells. | [[Image:2zwh.png|left|200px|thumb|Crystal Structure of F-actin, [[2zwh]]]]'''Filamentous actin''' ('''F-actin''') units are also referred to as [http://en.wikipedia.org/wiki/microfilament microfilaments] <ref> Microfilaments - Wikipedia, the free encyclopedia. http://en.wikipedia.org/wiki/Microfilament. Date accessed: March 16th, 2010. </ref> and are highly conserved, proteinous components found near ubiquitously in eukaryotic cytoskeletons. F-actin and other [[actin]] proteins generally have structural roles in cells. | ||
{{TOC limit|2}} | |||
== Introduction == | == Introduction == | ||
Actin is found in nearly all eukaryotic cells and is known primarily for its function as a structural and translocation protein. It also has an ATPase function, as it hydrolyzes ATP to ADP and P<sub>i</sub> and undergoes conformational changes with each hydrolysis. Actin belongs to the actin superfamily, which includes other proteins such as Hsp70(DnaK), Hsc70, and hexokinase, because of its nucleotide-dependent conformational change<ref name="Graceffa">PMID:12813032</ref>. Because of the similarity observed in ''Escherichia Coli'''s, Hsc70 and ATPase domain of actin, it is believed that the two proteins have a common ancestry<ref name="Holmes1">PMID:19158779</ref>. Prokaryotes are not known to have actin, but do however have an actin homologue, MreB, which also leads to the idea of possible common ancestory<ref name="Holmes2">PMID:2395461</ref>. | Actin is found in nearly all eukaryotic cells and is known primarily for its function as a structural and translocation protein. It also has an ATPase function, as it hydrolyzes ATP to ADP and P<sub>i</sub> and undergoes conformational changes with each hydrolysis. Actin belongs to the actin superfamily, which includes other proteins such as Hsp70(DnaK), Hsc70, and hexokinase, because of its nucleotide-dependent conformational change<ref name="Graceffa">PMID:12813032</ref>. Because of the similarity observed in ''Escherichia Coli'''s, Hsc70 and ATPase domain of actin, it is believed that the two proteins have a common ancestry<ref name="Holmes1">PMID:19158779</ref>. Prokaryotes are not known to have actin, but do however have an actin homologue, MreB, which also leads to the idea of possible common ancestory<ref name="Holmes2">PMID:2395461</ref>. | ||
Actin occurs in two forms: globular actin (G-actin), the free monomeric units of actin, and filamentous actin (F-actin) which is the polymer form. These two forms exist in a dynamic equilibrium with one another as ATP-associated polymerization and depolymerization occur continuously within the cell. The monomer units in the F-actin possess a form that is distinct from the free monomeric form and it is a result of that change that the more specific ATPase activity may be observed. | Actin occurs in two forms: globular actin (G-actin), the free monomeric units of actin, and filamentous actin (F-actin) which is the polymer form. These two forms exist in a dynamic equilibrium with one another as ATP-associated polymerization and depolymerization occur continuously within the cell. The monomer units in the F-actin possess a form that is distinct from the free monomeric form and it is a result of that change that the more specific ATPase activity may be observed. | ||
== Assembly == | == Assembly == | ||
<applet load='1j6z' size='250' color='black' frame='true' align='left' caption='Globular Actin (G-actin): PDB identifier [http://www.rcsb.org/pdb/explore/explore.do?structureId=1J6Z 1J6Z].' scene='Sandbox_154/1j6z_black_true/2'/> | <applet load='1j6z' size='250' color='black' frame='true' align='left' caption='Globular Actin (G-actin): PDB identifier [http://www.rcsb.org/pdb/explore/explore.do?structureId=1J6Z 1J6Z].' scene='Sandbox_154/1j6z_black_true/2'/> | ||
