PLC beta 3 Gq: Difference between revisions

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==Unique bidirectional interactions of Phospholipase C beta 3 with G alpha Q==

== Introduction ==

Phospholipase C (PLC) catalyzes the hydrolysis of phosphatidylinositol 4,5-bisphosphate [IP2] to the second messengers inositol 1,4,5-trisphosphate [IP3] and diacylglycerol [DAG] in an essential step for many physiological cascades. When the receptor is stimulated by ligand of some kind it increase exchange of guanosine diphosphate (GDP) for guanosine triphosphate (GTP) on Gαq. GTP-bound Gαq activates PLC- β3, and PLC- β3 increases up to three orders of magnitude the rate of hydrolysis of GTP by its activating G protein. This is a unique mechanism when the PLC-β3 enzyme has the ability to terminate the Gαq protein signal in addition to being activated by it.<ref>PMID:20966218</ref> <ref>PMID:23880553</ref>

== Structural highlights ==

The Gαq subunit consists two domains, one is the GTPase domain and the other is the alpha helical domain. These domains include three regions called <scene name='70/701452/Fig2/2'>switch regions I-III</scene>.

<scene name='70/701452/Fig1/9'>The PLC- β3 has several domains</scene> consisting of N-terminal PH domain, a series of four EF hands, a catalytic TIM barrel that the X/Y linker connect its two halves and a C2 domain.<ref>PMID:20966218</ref>

PLC- β3 engages Gαq throughout three regions. First, an extended loop between the third and fourth EF hands of PLC- β3 directly supports switch residues critical for GTP hydrolysis by Gαq. Second, the region of PLC- β3 that connects the catalytic TIM barrel and the C2 domain interacts with both switches 1 and 2 of Gαq. Third, a segment composed of a helix-turn-helix at the C terminus of the C2 domain mostly located within a shallow declivity on the surface of Gαq formed by switch 2 and α3.~~<ref>PMID:20966218</ref>~~

<scene name='70/701452/Fig1/9'>The PLC- β3 has several domains</scene> consisting of N-terminal PH domain, a series of four EF hands, a catalytic TIM barrel that the X/Y linker connect its two halves and a C2 domain.

PLC- β3 engages Gαq throughout three regions. First, an extended loop between the third and fourth EF hands of PLC- β3 directly supports switch residues critical for GTP hydrolysis by Gαq. Second, the region of PLC- β3 that connects the catalytic TIM barrel and the C2 domain interacts with both switches 1 and 2 of Gαq. Third, a segment composed of a helix-turn-helix at the C terminus of the C2 domain mostly located within a shallow declivity on the surface of Gαq formed by switch 2 and α3.

PLC-β3 interacts with a surface on Gαq that overlaps almost completely with portions of Gα subunits needed for engagement of RGS proteins and the effector-binding region. Other effectors are known to engage the effector-binding site within Gα subunits. There are a large family of regulator of G protein signaling (RGS) proteins that independently accelerates the GTP hydrolysis in the GTPase domain. ~~<ref>PMID:20966218</ref>~~

PLC-β3 interacts with a surface on Gαq that overlaps almost completely with portions of Gα subunits needed for engagement of RGS proteins and the effector-binding region. Other effectors are known to engage the effector-binding site within Gα subunits. There are a large family of regulator of G protein signaling (RGS) proteins that independently accelerates the GTP hydrolysis in the GTPase domain.

PLC beta 3 Gq: Difference between revisions

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 ==Unique bidirectional interactions of Phospholipase C beta 3 with G alpha Q==
 <StructureSection load='3ohm' size='340' side='right' caption='Caption for this structure' scene=''>
 == Introduction ==
 Phospholipase C (PLC) catalyzes the hydrolysis of phosphatidylinositol 4,5-bisphosphate [IP2] to the second messengers inositol 1,4,5-trisphosphate [IP3] and diacylglycerol [DAG] in an essential step for many physiological cascades. When the receptor is stimulated by ligand of some kind it increase exchange of guanosine diphosphate (GDP) for guanosine triphosphate (GTP) on Gαq. GTP-bound Gαq activates PLC- β3, and PLC- β3 increases up to three orders of magnitude the rate of hydrolysis of GTP by its activating G protein. This is a unique mechanism when the PLC-β3 enzyme has the ability to terminate the Gαq protein signal in addition to being activated by it.<ref>PMID:20966218</ref> <ref>PMID:23880553</ref>
 == Structural highlights ==
 The Gαq subunit consists two domains, one is the GTPase domain and the other is the alpha helical domain. These domains include three regions called <scene name='70/701452/Fig2/2'>switch regions I-III</scene>.
-<scene name='70/701452/Fig1/9'>The PLC- β3 has several domains</scene> consisting of N-terminal PH domain, a series of four EF hands, a catalytic TIM barrel that the X/Y linker connect its two halves and a C2 domain.<ref>PMID:20966218</ref>
-PLC- β3 engages Gαq throughout three regions. First, an extended loop between the third and fourth EF hands of PLC- β3 directly supports switch residues critical for GTP hydrolysis by Gαq. Second, the region of PLC- β3 that connects the catalytic TIM barrel and the C2 domain interacts with both switches 1 and 2 of Gαq. Third, a segment composed of a helix-turn-helix at the C terminus of the C2 domain mostly located within a shallow declivity on the surface of Gαq formed by switch 2 and α3.<ref>PMID:20966218</ref>
+<scene name='70/701452/Fig1/9'>The PLC- β3 has several domains</scene> consisting of N-terminal PH domain, a series of four EF hands, a catalytic TIM barrel that the X/Y linker connect its two halves and a C2 domain.
+PLC- β3 engages Gαq throughout three regions. First, an extended loop between the third and fourth EF hands of PLC- β3 directly supports switch residues critical for GTP hydrolysis by Gαq. Second, the region of PLC- β3 that connects the catalytic TIM barrel and the C2 domain interacts with both switches 1 and 2 of Gαq. Third, a segment composed of a helix-turn-helix at the C terminus of the C2 domain mostly located within a shallow declivity on the surface of Gαq formed by switch 2 and α3.
- PLC-β3 interacts with a surface on Gαq that overlaps almost completely with portions of Gα subunits needed for engagement of RGS proteins and the effector-binding region. Other effectors are known to engage the effector-binding site within Gα subunits. There are a large family of regulator of G protein signaling (RGS) proteins that independently accelerates the GTP hydrolysis in the GTPase domain. <ref>PMID:20966218</ref>
+PLC-β3 interacts with a surface on Gαq that overlaps almost completely with portions of Gα subunits needed for engagement of RGS proteins and the effector-binding region. Other effectors are known to engage the effector-binding site within Gα subunits. There are a large family of regulator of G protein signaling (RGS) proteins that independently accelerates the GTP hydrolysis in the GTPase domain.