Degradation signals within both terminal domains of the cauliflower mosaicvirus capsid protein precursor

Citation
A. Karsies et al., Degradation signals within both terminal domains of the cauliflower mosaicvirus capsid protein precursor, PLANT J, 27(4), 2001, pp. 335-343
Citations number
36
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Plant Sciences","Animal & Plant Sciences
Journal title
PLANT JOURNAL
ISSN journal
0960-7412 → ACNP
Volume
27
Issue
4
Year of publication
2001
Pages
335 - 343
Database
ISI
SICI code
0960-7412(200108)27:4<335:DSWBTD>2.0.ZU;2-5
Abstract
Targeted protein degradation plays an important regulatory role in the cell , but only a few protein degradation signals have been characterized in pla nts. Here we describe three instability determinants in the termini of the cauliflower mosaic virus (CaMV) capsid protein precursor, of which one is s till present in the mature capsid protein p44. A modified ubiquitin protein reference technique was used to show that these motifs are still active wh en fused to a heterologous reporter gene. The N-terminus of p44 contains a degradation motif characterized by proline, glutamate, aspartate, serine an d threonine residues (PEST), which can be inactivated by mutation of three glutamic acid residues to alanines. The signals from the precursor do not c orrespond to known degradation motifs, although they confer high instabilit y on proteins expressed in plant protoplasts. All three instability determi nants were also active in mammalian cells. The PEST signal had a significan tly higher degradation activity in HeLa cells, whereas the precursor signal s were less active. Inhibition studies suggest that only the signal within the N-terminus of the precursor is targeting the proteasome in plants. This implies that the other two signals may target a novel degradation pathway.