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United States Department of Agriculture

Agricultural Research Service

Title: Characterization of the Arabidopsis Thaliana Importin-Alpha Family of Receptor/chaperone Proteins


Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: August 3, 2002
Publication Date: N/A

Technical Abstract: Most nuclear proteins are targeted via poly-basic primary sequence motifs called nuclear localization signals (NLS). The first step in nuclear import is cytoplasmic recognition and binding of NLS sequences by the importin-alpha receptor/chaperone proteins. To better understand nucleocytoplasmic protein trafficking in plant cells, we have begun analysis of the importin-alpha proteins from Aribidopsis thaliana (AtIMPa). Analysis of the genome revealed a family of nine members, AtIMPa1-9. The IMPa proteins comprise, from the N-terminus, an importin-alpha binding motif, 6-9 armadillo repeat motifs, and a C-terminal acidic patch. The AtIMPa proteins vary from 49.3 to 59.4 kDa, with pI values from 4.6 to 5.5. Digital Northern analysis revealed that 1, 2, and 4 are the most highly expressed, 3 and 6 are moderately expressed, and the remainder are expressed at a low level. Experiments have been initiated, using two-hybrid analysis of the atDjC6 chaperone protein, to test specificity of NLS sequence binding.

Last Modified: 4/22/2015
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