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Subunits of the Drosophila actin-capping protein heterodimer regulate each other at multiple levels.

Amândio AR, Gaspar P, Whited JL, Janody F - PLoS ONE (2014)

Bottom Line: Overexpressing capping protein α and β decreases both F-actin levels and tissue growth, while expressing forms of Capping Protein that have dominant negative effects on F-actin promote tissue growth.Both subunits regulate each other's protein levels.In addition, overexpressing one of the subunit in tissues knocked-down for the other increases the mRNA and protein levels of the subunit knocked-down and compensates for its loss.

View Article: PubMed Central - PubMed

Affiliation: Instituto Gulbenkian de Ciência, Oeiras, Portugal.

ABSTRACT
The actin-Capping Protein heterodimer, composed of the α and β subunits, is a master F-actin regulator. In addition to its role in many cellular processes, Capping Protein acts as a main tumor suppressor module in Drosophila and in humans, in part, by restricting the activity of Yorkie/YAP/TAZ oncogenes. We aimed in this report to understand how both subunits regulate each other in vivo. We show that the levels and capping activities of both subunits must be tightly regulated to control F-actin levels and consequently growth of the Drosophila wing. Overexpressing capping protein α and β decreases both F-actin levels and tissue growth, while expressing forms of Capping Protein that have dominant negative effects on F-actin promote tissue growth. Both subunits regulate each other's protein levels. In addition, overexpressing one of the subunit in tissues knocked-down for the other increases the mRNA and protein levels of the subunit knocked-down and compensates for its loss. We propose that the ability of the α and β subunits to control each other's levels assures that a pool of functional heterodimer is produced in sufficient quantities to restrict the development of tumor but not in excess to sustain normal tissue growth.

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Related in: MedlinePlus

Overexpressing full length HA-cpa and cpb prevents wing growth, while ectopic expression of HA-cpaΔABD and/or cpbL262R has the opposite effect.(A, B, C, D and E) merge between adult wings expressing in green UAS-mCD8GFP under nub-Gal4 control and in magenta (A) UAS-HA-cpa89E and UAS-cpb7 or (B) UAS-HA-cpaΔABD and UAS-cpb7 or (C) UAS-cpbL262R and one copy of UAS-mCD8-GFP or (D) UAS-cpbL262R and UAS-HA-cpa89E or (E) UAS-cpbL262R and UAS-HA-cpaΔABD under nub-Gal4 control. (A′, B′, C′ D′ and E′) magnification of hairs on adult wings for the genotypes shown in A, B, C, D and E. (F) quantification of relative wing size normalized to nub>GFP control for nub-Gal4 driving UAS-mCD8-GFP (lane 1) or UAS-HA-cpa89E and UAS-cpb7 (lane 2) or UAS-HA-cpaΔABD and UAS-cpb7 (lane 3) or UAS-cpbL262R and one copy of UAS-mCD8-GFP (lane 4) or UAS-cpbL262R and UAS-HA-cpa89E (lane 5) or UAS-cpbL262R and UAS-HA-cpaΔABD (lane 6). The mean for lane 1 is 1(n = 32), for lane 2 is 0.9702 (n = 12), for lane 3 is 1.119 (n = 13), for lane 4 is 1.061 (n = 24), for lane 5 is 1.015 (n = 13), for lane 6 is 1.051 (n = 13). Error bars indicate s.e.m.. P<0.015 for comparison of lanes 1 and 2. P<0.0001 for comparison of lanes 1 and 3 or 4 or 6 and for comparison of lane 4 and 5.
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pone-0096326-g004: Overexpressing full length HA-cpa and cpb prevents wing growth, while ectopic expression of HA-cpaΔABD and/or cpbL262R has the opposite effect.(A, B, C, D and E) merge between adult wings expressing in green UAS-mCD8GFP under nub-Gal4 control and in magenta (A) UAS-HA-cpa89E and UAS-cpb7 or (B) UAS-HA-cpaΔABD and UAS-cpb7 or (C) UAS-cpbL262R and one copy of UAS-mCD8-GFP or (D) UAS-cpbL262R and UAS-HA-cpa89E or (E) UAS-cpbL262R and UAS-HA-cpaΔABD under nub-Gal4 control. (A′, B′, C′ D′ and E′) magnification of hairs on adult wings for the genotypes shown in A, B, C, D and E. (F) quantification of relative wing size normalized to nub>GFP control for nub-Gal4 driving UAS-mCD8-GFP (lane 1) or UAS-HA-cpa89E and UAS-cpb7 (lane 2) or UAS-HA-cpaΔABD and UAS-cpb7 (lane 3) or UAS-cpbL262R and one copy of UAS-mCD8-GFP (lane 4) or UAS-cpbL262R and UAS-HA-cpa89E (lane 5) or UAS-cpbL262R and UAS-HA-cpaΔABD (lane 6). The mean for lane 1 is 1(n = 32), for lane 2 is 0.9702 (n = 12), for lane 3 is 1.119 (n = 13), for lane 4 is 1.061 (n = 24), for lane 5 is 1.015 (n = 13), for lane 6 is 1.051 (n = 13). Error bars indicate s.e.m.. P<0.015 for comparison of lanes 1 and 2. P<0.0001 for comparison of lanes 1 and 3 or 4 or 6 and for comparison of lane 4 and 5.

Mentions: Decreasing or increasing CP levels has opposite effects on F-actin levels (Fig. 3F and [25]). Because loss of CP induces overgrowth of the wing disc epithelium by promoting Yki activity [7], [9], we asked of overexpressing cpa and cpb has an opposite effect on tissue growth. Indeed, overexpressing full length HA-cpa and cpb in the wing primordium using the nubbin-Gal4 (nub-Gal4) driver significantly reduced the size of the adult wing (Fig. 4A, compare nub>GFP control wing in green to nub>cpa+, cpb+ wing in magenta and F; P<0.0151), but does not affect cell survival [21]. Thus, tight CP levels are critical to control tissue growth.


Subunits of the Drosophila actin-capping protein heterodimer regulate each other at multiple levels.

Amândio AR, Gaspar P, Whited JL, Janody F - PLoS ONE (2014)

Overexpressing full length HA-cpa and cpb prevents wing growth, while ectopic expression of HA-cpaΔABD and/or cpbL262R has the opposite effect.(A, B, C, D and E) merge between adult wings expressing in green UAS-mCD8GFP under nub-Gal4 control and in magenta (A) UAS-HA-cpa89E and UAS-cpb7 or (B) UAS-HA-cpaΔABD and UAS-cpb7 or (C) UAS-cpbL262R and one copy of UAS-mCD8-GFP or (D) UAS-cpbL262R and UAS-HA-cpa89E or (E) UAS-cpbL262R and UAS-HA-cpaΔABD under nub-Gal4 control. (A′, B′, C′ D′ and E′) magnification of hairs on adult wings for the genotypes shown in A, B, C, D and E. (F) quantification of relative wing size normalized to nub>GFP control for nub-Gal4 driving UAS-mCD8-GFP (lane 1) or UAS-HA-cpa89E and UAS-cpb7 (lane 2) or UAS-HA-cpaΔABD and UAS-cpb7 (lane 3) or UAS-cpbL262R and one copy of UAS-mCD8-GFP (lane 4) or UAS-cpbL262R and UAS-HA-cpa89E (lane 5) or UAS-cpbL262R and UAS-HA-cpaΔABD (lane 6). The mean for lane 1 is 1(n = 32), for lane 2 is 0.9702 (n = 12), for lane 3 is 1.119 (n = 13), for lane 4 is 1.061 (n = 24), for lane 5 is 1.015 (n = 13), for lane 6 is 1.051 (n = 13). Error bars indicate s.e.m.. P<0.015 for comparison of lanes 1 and 2. P<0.0001 for comparison of lanes 1 and 3 or 4 or 6 and for comparison of lane 4 and 5.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4008575&req=5

pone-0096326-g004: Overexpressing full length HA-cpa and cpb prevents wing growth, while ectopic expression of HA-cpaΔABD and/or cpbL262R has the opposite effect.(A, B, C, D and E) merge between adult wings expressing in green UAS-mCD8GFP under nub-Gal4 control and in magenta (A) UAS-HA-cpa89E and UAS-cpb7 or (B) UAS-HA-cpaΔABD and UAS-cpb7 or (C) UAS-cpbL262R and one copy of UAS-mCD8-GFP or (D) UAS-cpbL262R and UAS-HA-cpa89E or (E) UAS-cpbL262R and UAS-HA-cpaΔABD under nub-Gal4 control. (A′, B′, C′ D′ and E′) magnification of hairs on adult wings for the genotypes shown in A, B, C, D and E. (F) quantification of relative wing size normalized to nub>GFP control for nub-Gal4 driving UAS-mCD8-GFP (lane 1) or UAS-HA-cpa89E and UAS-cpb7 (lane 2) or UAS-HA-cpaΔABD and UAS-cpb7 (lane 3) or UAS-cpbL262R and one copy of UAS-mCD8-GFP (lane 4) or UAS-cpbL262R and UAS-HA-cpa89E (lane 5) or UAS-cpbL262R and UAS-HA-cpaΔABD (lane 6). The mean for lane 1 is 1(n = 32), for lane 2 is 0.9702 (n = 12), for lane 3 is 1.119 (n = 13), for lane 4 is 1.061 (n = 24), for lane 5 is 1.015 (n = 13), for lane 6 is 1.051 (n = 13). Error bars indicate s.e.m.. P<0.015 for comparison of lanes 1 and 2. P<0.0001 for comparison of lanes 1 and 3 or 4 or 6 and for comparison of lane 4 and 5.
Mentions: Decreasing or increasing CP levels has opposite effects on F-actin levels (Fig. 3F and [25]). Because loss of CP induces overgrowth of the wing disc epithelium by promoting Yki activity [7], [9], we asked of overexpressing cpa and cpb has an opposite effect on tissue growth. Indeed, overexpressing full length HA-cpa and cpb in the wing primordium using the nubbin-Gal4 (nub-Gal4) driver significantly reduced the size of the adult wing (Fig. 4A, compare nub>GFP control wing in green to nub>cpa+, cpb+ wing in magenta and F; P<0.0151), but does not affect cell survival [21]. Thus, tight CP levels are critical to control tissue growth.

Bottom Line: Overexpressing capping protein α and β decreases both F-actin levels and tissue growth, while expressing forms of Capping Protein that have dominant negative effects on F-actin promote tissue growth.Both subunits regulate each other's protein levels.In addition, overexpressing one of the subunit in tissues knocked-down for the other increases the mRNA and protein levels of the subunit knocked-down and compensates for its loss.

View Article: PubMed Central - PubMed

Affiliation: Instituto Gulbenkian de Ciência, Oeiras, Portugal.

ABSTRACT
The actin-Capping Protein heterodimer, composed of the α and β subunits, is a master F-actin regulator. In addition to its role in many cellular processes, Capping Protein acts as a main tumor suppressor module in Drosophila and in humans, in part, by restricting the activity of Yorkie/YAP/TAZ oncogenes. We aimed in this report to understand how both subunits regulate each other in vivo. We show that the levels and capping activities of both subunits must be tightly regulated to control F-actin levels and consequently growth of the Drosophila wing. Overexpressing capping protein α and β decreases both F-actin levels and tissue growth, while expressing forms of Capping Protein that have dominant negative effects on F-actin promote tissue growth. Both subunits regulate each other's protein levels. In addition, overexpressing one of the subunit in tissues knocked-down for the other increases the mRNA and protein levels of the subunit knocked-down and compensates for its loss. We propose that the ability of the α and β subunits to control each other's levels assures that a pool of functional heterodimer is produced in sufficient quantities to restrict the development of tumor but not in excess to sustain normal tissue growth.

Show MeSH
Related in: MedlinePlus