Reference Report

Reference
Citation	Fletcher, G.C., Lucas, E.P., Brain, R., Tournier, A., Thompson, B.J. (2012). Positive feedback and mutual antagonism combine to polarize crumbs in the Drosophila follicle cell epithelium. Curr. Biol. 22(12): 1116--1122. (Export to RIS)
FlyBase ID	FBrf0218646
Publication Type	Research paper
PubMed ID	22658591
PubMed Abstract	Epithelial tissues are composed of polarized cells with distinct apical and basolateral membrane domains. In the Drosophila ovarian follicle cell epithelium, apical membranes are specified by Crumbs (Crb), Stardust (Sdt), and the aPKC-Par6-cdc42 complex. Basolateral membranes are specified by Lethal giant larvae (Lgl), Discs large (Dlg), and Scribble (Scrib). Apical and basolateral determinants are known to act in a mutually antagonistic fashion, but it remains unclear how this interaction generates polarity. We have built a computer model of apicobasal polarity that suggests that the combination of positive feedback among apical determinants plus mutual antagonism between apical and basal determinants is essential for polarization. In agreement with this model, in vivo experiments define a positive feedback loop in which Crb self-recruits via Crb-Crb extracellular domain interactions, recruitment of Sdt-aPKC-Par6-cdc42, aPKC phosphorylation of Crb, and recruitment of Expanded (Ex) and Kibra (Kib) to prevent endocytic removal of Crb from the plasma membrane. Lgl antagonizes the operation of this feedback loop, explaining why apical determinants do not normally spread into the basolateral domain. Once Crb is removed from the plasma membrane, it undergoes recycling via Rab11 endosomes. Our results provide a dynamic model for understanding how epithelial polarity is maintained in Drosophila follicle cells.
DOI	10.1016/j.cub.2012.04.020
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Language of Publication	English
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Publication Type	Journal
Abbreviation	Curr. Biol.
Title	Current Biology
Publication Year	1991-
ISBN/ISSN	0960-9822
Data from Reference
Alleles (16)
	aPKC^k06403 aPKC^psu417 aPKC^ΔN.Scer\UAS Cdc42³ Cdc42^{Scer\UAS.T:SV5\V5} Cdc42^V12.Scer\UAS crb^11A22 crb^{extraTM.Scer\UAS.T:Avic\GFP} crb^{intra.Scer\UAS} crb^{P-mut.Scer\UAS} crb^Scer\UAS.cWa ex^e1 kibra^Δ32 Scer\GAL4^Act.PU Scer\GAL4^GR1 Scer\GAL4^tub.PU
Constructs (7)
	P{UAS-aPKC.ΔN} P{UAS-Cdc42.V5} P{UAS-Cdc42.V12} P{UAS-crb.extra.TM-GFP} P{UAS-crb.intra} P{UAS-crb.P-mut} P{UAS-crb.wt}
Genes (14)
	AP-2μ aPKC Cdc42 crb dlg1 ex kibra l(2)gl par-6 Rab5 Rab11 Scer\GAL4 sdt T:SV5\V5
Natural transposons (1)
	P-element