E3-independent ubiquitination of AtMAPR/MSBP1

Ai-Ling Kao; Ying-Han Lin; Rita P-Y Chen; Yun-Yen Huang; Ching-Chung Chen; Chien-Chih Yang

doi:10.1016/j.phytochem.2012.03.006

E3-independent ubiquitination of AtMAPR/MSBP1

Phytochemistry. 2012 Jun:78:7-19. doi: 10.1016/j.phytochem.2012.03.006. Epub 2012 Apr 16.

Authors

Ai-Ling Kao¹, Ying-Han Lin, Rita P-Y Chen, Yun-Yen Huang, Ching-Chung Chen, Chien-Chih Yang

Affiliation

¹ Institute of Microbiology and Biochemistry, National Taiwan University, Taiwan.

PMID: 22513011
DOI: 10.1016/j.phytochem.2012.03.006

Abstract

AtMAPR5/MSBP1 and its homologs can be ubiquitinated in the absence of E3 ligase in in vitro ubiquitination assays. Ubiquitinated AtMAPR3, AtMAPR5/MSBP1, and AtMAPR2 were identified using LC-MS/MS. Analysis of trypsin-released signature peptides showed that this E3-independent ubiquitination of AtMAPR3, AtMAPR5/MSBP1, and AtMAPR2 was dominated by mono-ubiquitination at multiple sites. Unlike AtUBC8-type E2s, AtUBC36 was not able to transfer ubiquitin to AtMAPR2. The truncated mutants AtMAPR2Δ1-10, AtMAPR2Δ1-30, and AtMAPR2_1-73 could also be ubiquitinated. The presence of a ubiquitin-binding domain (UBD) allows proteins to be ubiquitinated independently of E3 ligases. However, AtMAPRs do not contain any known UBD. In vitro ubiquitination of AtMAPR2 observed in this study will be further studied in biochemical and physiological aspects.

MeSH terms

Arabidopsis / enzymology*
Arabidopsis / metabolism
Arabidopsis Proteins / metabolism*
Carrier Proteins / metabolism*
Electrophoresis, Polyacrylamide Gel
Humans
Ubiquitin-Protein Ligases / metabolism*
Ubiquitination / physiology*

Substances

Arabidopsis Proteins
Carrier Proteins
MSBP1 protein, Arabidopsis
Ubiquitin-Protein Ligases