Xenopus Kazrin interacts with ARVCF-catenin, spectrin and p190B RhoGAP, and modulates RhoA activity and epithelial integrity.
In common with other p120-catenin subfamily members, Xenopus ARVCF (xARVCF) binds cadherin cytoplasmic domains to enhance cadherin metabolic stability or, when dissociated, modulates Rho-family GTPases. We report here that xARVCF binds and is stabilized by Xenopus KazrinA (xKazrinA), a widely expressed conserved protein that bears little homology to established protein families, and which is known to influence keratinocyte proliferation and differentiation and cytoskeletal activity. Although we found that xKazrinA binds directly to xARVCF, we did not resolve xKazrinA within a larger ternary complex with cadherin, nor did it co-precipitate with core desmosomal components. Instead, screening revealed that xKazrinA binds spectrin, suggesting a potential means by which xKazrinA localizes to cell-cell borders. This was supported by the resolution of a ternary biochemical complex of xARVCF-xKazrinA-xβ2-spectrin and, in vivo, by the finding that ectodermal shedding followed depletion of xKazrin in Xenopus embryos, a phenotype partially rescued with exogenous xARVCF. Cell shedding appeared to be the consequence of RhoA activation, and thereby altered actin organization and cadherin function. Indeed, we also revealed that xKazrinA binds p190B RhoGAP, which was likewise capable of rescuing Kazrin depletion. Finally, xKazrinA was found to associate with δ-catenins and p0071-catenins but not with p120-catenin, suggesting that Kazrin interacts selectively with additional members of the p120-catenin subfamily. Taken together, our study supports the essential role of Kazrin in development, and reveals the biochemical and functional association of KazrinA with ARVCF-catenin, spectrin and p190B RhoGAP.
Department of Biochemistry and Molecular Biology, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
Kyucheol
K
Cho
Travis G
TG
Vaught
Hong
H
Ji
Dongmin
D
Gu
Catherine
C
Papasakelariou-Yared
Nicola
N
Horstmann
Jean Marie
JM
Jennings
Moonsup
M
Lee
Lisa M
LM
Sevilla
Malgorzata
M
Kloc
Albert B
AB
Reynolds
Fiona M
FM
Watt
Richard G
RG
Brennan
Andrew P
AP
Kowalczyk
Pierre D
PD
McCrea
D000818:Animals; D051186:Armadillo Domain Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015820:Cadherins / Q000235:genetics / Q000378:metabolism*; D015815:Cell Adhesion Molecules / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D004847:Epithelial Cells / Q000737:chemistry / Q000201:enzymology / Q000378:metabolism*; D020690:GTPase-Activating Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010750:Phosphoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D013049:Spectrin / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D014981:Xenopus / Q000235:genetics / Q000378:metabolism*; D029867:Xenopus Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*
D051186:Armadillo Domain Proteins; D015820:Cadherins; D015815:Cell Adhesion Molecules; D020690:GTPase-Activating Proteins; C556503:KAZN protein, Xenopus; D008565:Membrane Proteins; D010750:Phosphoproteins; D029867:Xenopus Proteins; C485847:arvcf protein, Xenopus; C556502:p190B RhoGAP, Xenopus; D013049:Spectrin; D020742:rhoA GTP-Binding Protein