Sandbox Reserved 705: Difference between revisions
From Proteopedia
Jump to navigationJump to search
No edit summary |
No edit summary |
||
| Line 15: | Line 15: | ||
ERM proteins link Adhrens Junctions to the actin cytoskeleton,and are able to remodel Adherens Junctions during epithelial morphogenesis. | ERM proteins link Adhrens Junctions to the actin cytoskeleton,and are able to remodel Adherens Junctions during epithelial morphogenesis. | ||
They also maintain the organization of apical surfaces on the plasma membrane <ref>PMID:11329377</ref>. | They also maintain the organization of apical surfaces on the plasma membrane <ref>PMID:11329377</ref>. | ||
===Structural organization=== | |||
All these proteins have an about 300-residue globular plasma membrane-associated FERM domain(four-point-one ezrin, radixin, moesin).This FERM domain is a highly conserved domain. This domain is divided into three subdomains (F1, F2, and F3). | All these proteins have an about 300-residue globular plasma membrane-associated FERM domain(four-point-one ezrin, radixin, moesin).This FERM domain is a highly conserved domain. This domain is divided into three subdomains (F1, F2, and F3). | ||
ERM proteins are composed of a FERM domain followed by a long region with a high α-helical propensity and terminating in a C-terminal domain<ref name="utile">PMID:20308985</ref>. | ERM proteins are composed of a FERM domain followed by a long region with a high α-helical propensity and terminating in a C-terminal domain<ref name="utile">PMID:20308985</ref>. | ||
[[Image:imagevraie.gif |thumb|center|650px|Domain organization of ERM<ref name="utile" />]] | [[Image:imagevraie.gif |thumb|center|650px|Domain organization of ERM<ref name="utile" />]] | ||
===Regulation of the activity=== | |||
The acitivity of ERM proteins is caused by the association of different regions within the protein. | The acitivity of ERM proteins is caused by the association of different regions within the protein. | ||
The C-terminal tail domain contains an F-actin binding site in the last 30 residues. This domain interacts with the FERM domain as an extended, meandering polypeptide beginning with a β-strand associated with β5 in F3 followed by four helices | The C-terminal tail domain contains an F-actin binding site in the last 30 residues. This domain interacts with the FERM domain as an extended, meandering polypeptide beginning with a β-strand associated with β5 in F3 followed by four helices. The two first helices bind l and the two second lobe F3. The FERM-tail complex represents an inactive form of the protein in which membrane protein and active binding sites are masked.<ref>PMID:17134719</ref> | ||
The ERM proteins are regulated by changing from a closed conformation to an open, active state. This is due to severing of intramolecular head–tail interactions,and also | The ERM proteins are regulated by changing from a closed conformation to an open, active state. This is due to severing of intramolecular head–tail interactions,and also of interactions between their FERM domain and α-helical domains<ref name="utile2">PMID:22012890</ref>.Conformational changes modify the intramolecular contacts, allowing these proteins to bind to their partners. The protein is in an active state. | ||
===Regulators of the activity=== | |||
Phosphorylation of a C-terminal threonine by Rho kinase and binding to phosphatidylinositol 4,5-bisphosphate (PIP2) and protein partners, is necessary for full activation of ERM proteins <ref>PMID:14993232</ref>. They disrupt the head to tail interactions. The phosphorylations and/binding(s) determine the cellular localization and the cellular function of each specific ERM protein. | Phosphorylation of a C-terminal threonine by Rho kinase and binding to phosphatidylinositol 4,5-bisphosphate (PIP2) and protein partners, is necessary for full activation of ERM proteins <ref>PMID:14993232</ref>. They disrupt the head to tail interactions. The phosphorylations and/binding(s) determine the cellular localization and the cellular function of each specific ERM protein. | ||
'''PIP2 =phosphatidylinositol 4,5-bisphosphate marqué juste au dessus :) '''<ref>PMID:21402777</ref> | '''PIP2 =phosphatidylinositol 4,5-bisphosphate marqué juste au dessus :) '''<ref>PMID:21402777</ref> | ||
