UniProt release 10.3
Published April 17, 2007
Complete set of Arabidopsis thaliana F-box proteins
F-box proteins play a major role in the ubiquitin conjugation pathway. There are involved in the third step of this pathway. Most of the F-box protein contains a conserved F-box domain near the N-terminus and a variable region. The F-box domain can interact with Cullin and one of the SKP1 proteins to form a E3 SCF (SKP1/Cullin/F-box) ubiquitin ligase complex. The variable region interacts with a specific protein, which is, in turn, ubiquitinated and thus targeted to protein degradation. This variable region confers the specificity of the SCF complex.
The whole set of Arabidopsis thaliana, more than 630 F-box protein sequences, has been manually reviewed and integrated into UniProtKB/Swiss-Prot. About 120 wrong gene model predictions have been corrected, including 26 F-box proteins obtained by splitting erroneous gene predictions covering more than one gene. This represents one of the largest protein family of a given species that had ever been integrated into UniProtKB/Swiss-Prot.
In A. thaliana, almost half of F-box proteins contains a combination of different domains which is used to define subgroups:
|91||FBL||F-box associated with LRR-repeat|
|124||FBK||F-box associated with Kelch-repeat|
|30||FBD||F-box associated with FBD|
|41||FDL||F-box associated with FBD and LRR-repeat|
|4||FBLK||F-box associated with LRR-repeat and Kelch-repeat|
Among this large protein family, less than 30 members have been characterized: their functions are various and include flowering, circadian cycle, hormone signaling, and plant defense.
- a F-box protein involved in flowering (Q39090, UFO_ARATH)
- a F-box protein involved in circadian cycle (Q94BT6, ADO1_ARATH)
- a F-box protein involved in hormone signaling (Q570C0, TIR1_ARATH)
- a F-box protein involved in plant defense a F-box protein involved in plant defense (O04197, COI1_ARATH)
- Cullin (Q94AH6, CUL1_ARATH)
- SKP1A (Q39255, SKP1A_ARATH)
- Ubiquitin (P59263, UBIQ_ARATH)