Group:MUZIC:CapZ: Difference between revisions

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== Function and Interactions==

Capping protein binds to the barbed end with high affinity (Kd > 1 nM) with 1:1 stoichiometry and prevents the loss and addition of actin monomers. CapZ is important in the dynamics of actin filaments and is crucial for rapid filament elongation as a response to signaling. It does so by blocking the barbed ends, thus ensuring a high steady state concentration of G-actin in the cytoplasm <ref>PMID:12660160</ref>. The absence of capping protein prevented the reconstruction of motility in Shigella and Listeria, in vitro. CapZ plays a role in targeting the actin filaments to other structural components. The sarcomeric isoform interacts with α-actinin and anchors the thin filament system to the Z-disk <ref>PMID:16416311</ref>. Small interference RNA (siRNA) studies showed that knockdown of nebulin in chick skeletal myotubes leads to a reduction of assembled CapZ and a loss of the characteristic uniform alignment of the barbed ends of F-actin and this suggests that the interaction of CapZ and nebulin plays an important role in Z-disk architecture <ref>PMID:18272787</ref>. CapZ regulates the activity of cardiac protein kinase C (PKC): down regulation of CapZ leads to a decrease and alteration of the PKC signaling pathways. Cardiac CapZ regulates binding of PKC II to the myofilaments with effects on cardiac contractility <ref>PMID:21257757</ref>. Other binding partners of CapZ include the CARMIL protein, which further interacts with Arp complex2/3 and myosin I, both of which are key players in actin based cell motility <ref>PMID:12660160</ref>. In vivo the capping of actin filaments is regulated by second messengers PIP and PIP 2 (Phosphatidylinositol 4,5-bisphosphate), upon signal transduction these molecules promote removal of CapZ from actin filaments <ref>PMID:12663865</ref>.

Capping protein binds to the barbed end with high affinity (Kd > 1 nM) with 1:1 stoichiometry and prevents the loss and addition of actin monomers. CapZ is important in the dynamics of actin filaments and is crucial for rapid filament elongation as a response to signaling. It does so by blocking the barbed ends, thus ensuring a high steady state concentration of G-actin in the cytoplasm <ref>PMID:12660160</ref>. The absence of capping protein prevented the reconstruction of motility in Shigella and Listeria, in vitro. CapZ plays a role in targeting the actin filaments to other structural components. The sarcomeric isoform interacts with α-actinin and anchors the thin filament system to the Z-disk <ref>PMID:16416311</ref>. Small interference RNA (siRNA) studies showed that knockdown of nebulin in chick skeletal myotubes leads to a reduction of assembled CapZ and a loss of the characteristic uniform alignment of the barbed ends of F-actin and this suggests that the interaction of CapZ and nebulin plays an important role in Z-disk architecture <ref>PMID:18272787</ref>. CapZ regulates the activity of cardiac protein kinase C (PKC): down regulation of CapZ leads to a decrease and alteration of the PKC signaling pathways. Cardiac CapZ regulates binding of PKC II to the myofilaments with effects on cardiac contractility <ref>PMID:21257757</ref>,<ref>PMID:12089068</ref>. Other binding partners of CapZ include the CARMIL protein, which further interacts with Arp complex2/3 and myosin I, both of which are key players in actin based cell motility <ref>PMID:12660160</ref>. In vivo the capping of actin filaments is regulated by second messengers PIP and PIP 2 (Phosphatidylinositol 4,5-bisphosphate), upon signal transduction these molecules promote removal of CapZ from actin filaments <ref>PMID:12663865</ref>.

== Actin binding model ==

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 == Function and Interactions==
-Capping protein binds to the barbed end with high affinity (Kd > 1 nM) with 1:1 stoichiometry and prevents the loss and addition of actin monomers. CapZ is important in the dynamics of actin filaments and is crucial for rapid filament elongation as a response to signaling. It does so by blocking the barbed ends, thus ensuring a high steady state concentration of G-actin in the cytoplasm <ref>PMID:12660160</ref>. The absence of capping protein prevented the reconstruction of motility in Shigella and Listeria, in vitro. CapZ plays a role in targeting the actin filaments to other structural components. The sarcomeric isoform interacts with α-actinin and anchors the thin filament system to the Z-disk <ref>PMID:16416311</ref>. Small interference RNA (siRNA) studies showed that knockdown of nebulin in chick skeletal myotubes leads to a reduction of assembled CapZ and a loss of the characteristic uniform alignment of the barbed ends of F-actin and this suggests that the interaction of CapZ and nebulin plays an important role in Z-disk architecture <ref>PMID:18272787</ref>. CapZ regulates the activity of cardiac protein kinase C (PKC): down regulation of CapZ leads to a decrease and alteration of the PKC signaling pathways. Cardiac CapZ regulates binding of PKC II to the myofilaments with effects on cardiac contractility <ref>PMID:21257757</ref>. Other binding partners of CapZ include the CARMIL protein, which further interacts with Arp complex2/3 and myosin I, both of which are key players in actin based cell motility <ref>PMID:12660160</ref>. In vivo the capping of actin filaments is regulated by second messengers PIP and PIP 2 (Phosphatidylinositol 4,5-bisphosphate), upon signal transduction these molecules promote removal of CapZ from actin filaments <ref>PMID:12663865</ref>.
+Capping protein binds to the barbed end with high affinity (Kd > 1 nM) with 1:1 stoichiometry and prevents the loss and addition of actin monomers. CapZ is important in the dynamics of actin filaments and is crucial for rapid filament elongation as a response to signaling. It does so by blocking the barbed ends, thus ensuring a high steady state concentration of G-actin in the cytoplasm <ref>PMID:12660160</ref>. The absence of capping protein prevented the reconstruction of motility in Shigella and Listeria, in vitro. CapZ plays a role in targeting the actin filaments to other structural components. The sarcomeric isoform interacts with α-actinin and anchors the thin filament system to the Z-disk <ref>PMID:16416311</ref>. Small interference RNA (siRNA) studies showed that knockdown of nebulin in chick skeletal myotubes leads to a reduction of assembled CapZ and a loss of the characteristic uniform alignment of the barbed ends of F-actin and this suggests that the interaction of CapZ and nebulin plays an important role in Z-disk architecture <ref>PMID:18272787</ref>. CapZ regulates the activity of cardiac protein kinase C (PKC): down regulation of CapZ leads to a decrease and alteration of the PKC signaling pathways. Cardiac CapZ regulates binding of PKC II to the myofilaments with effects on cardiac contractility <ref>PMID:21257757</ref>,<ref>PMID:12089068</ref>. Other binding partners of CapZ include the CARMIL protein, which further interacts with Arp complex2/3 and myosin I, both of which are key players in actin based cell motility <ref>PMID:12660160</ref>. In vivo the capping of actin filaments is regulated by second messengers PIP and PIP 2 (Phosphatidylinositol 4,5-bisphosphate), upon signal transduction these molecules promote removal of CapZ from actin filaments <ref>PMID:12663865</ref>.
 == Actin binding model ==