Characterization of two distinct subfamilies of SUN-domain proteins in Arabidopsis and their interactions with the novel KASH-domain protein AtTIK.
J Exp Bot
; 65(22): 6499-512, 2014 Dec.
Article
em En
| MEDLINE
| ID: mdl-25217773
ABSTRACT
SUN-domain proteins belong to a gene family including classical Cter-SUN and mid-SUN subfamilies differentiated by the position of the SUN domain within the protein. Although present in animal and plant species, mid-SUN proteins have so far remained poorly described. Here, we used a combination of genetics, yeast two-hybrid and in planta transient expression methods to better characterize the SUN family in Arabidopsis thaliana. First, we validated the mid-SUN protein subfamily as a monophyletic group conserved from yeast to plant. Arabidopsis Cter-SUN (AtSUN1 and AtSUN2) and mid-SUN (AtSUN3 and AtSUN4) proteins expressed as fluorescent protein fusions are membrane-associated and localize to the nuclear envelope (NE) and endoplasmic reticulum. However, only the Cter-SUN subfamily is enriched at the NE. We investigated interactions in and between members of the two subfamilies and identified the coiled-coil domain as necessary for mediating interactions. The functional significance of the mid-SUN subfamily was further confirmed in mutant plants as essential for early seed development and involved in nuclear morphology. Finally, we demonstrated that both subfamilies interact with the KASH domain of AtWIP1 and identified a new root-specific KASH-domain protein, AtTIK. AtTIK localizes to the NE and affects nuclear morphology. Our study indicates that Arabidopsis Cter-SUN and mid-SUN proteins are involved in a complex protein network at the nuclear membranes, reminiscent of the LInker of Nucleoskeleton and Cytoskeleton (LINC) complex found in other kingdoms.
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1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Família Multigênica
/
Arabidopsis
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Proteínas de Arabidopsis
Idioma:
En
Revista:
J Exp Bot
Assunto da revista:
BOTANICA
Ano de publicação:
2014
Tipo de documento:
Article
País de afiliação:
Reino Unido