Q8AXF4 (FBX43_XENLA) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
F-box only protein 43

Alternative name(s):
Early mitotic inhibitor 2
Emi1-related protein 1
F-box protein 26
Xerp1

Gene names

Name:	fbxo43
Synonyms:	emi2, erp1, fbx26

Organism

Xenopus laevis (African clawed frog)

Taxonomic identifier

8355 [NCBI]

Taxonomic lineage

Eukaryota › Metazoa › Chordata › Craniata › Vertebrata › Euteleostomi › Amphibia › Batrachia › Anura › Mesobatrachia › Pipoidea › Pipidae › Xenopodinae › Xenopus › Xenopus

Protein attributes

Sequence length	651 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Required to prevent anaphase onset in cytostatic factor-arrested oocytes. Inhibits the anaphase-promoting complex/cyclosome (APC/C) ubiquitin ligase and prevents cyclin degradation. Probably recognizes and binds to some phosphorylated proteins and promotes their ubiquitination and degradation. Ref.2 Ref.3
Pathway	Protein modification; protein ubiquitination.
Subunit structure	Part of a SCF (SKP1-cullin-F-box) protein ligase complex By similarity.
Developmental stage	Accumulates during oocyte maturation. Ref.2
Post-translational modification	Phosphorylated on Thr-195 by CaMK2 in reponse to calcium during egg activation, which promotes subsequent phosphorylation by PLK1, ubiquitination and protesomal degradation. Ref.2 Ref.3 Ref.4 Ref.5 Ref.6 Ubiquitinated by FBXW1 during egg activation, which promotes proteasomal degradation. Ref.2 Ref.3
Sequence similarities	Contains 1 F-box domain. Contains 1 IBR-type zinc finger.
Sequence caution	The sequence AAF14554.1 differs from that shown. Reason: Frameshift at several positions. The sequence AAF14554.1 differs from that shown. Reason: Sequencing errors.

Ontologies

Keywords
Biological process	Meiosis Ubl conjugation pathway
Domain	Zinc-finger
Ligand	Metal-binding Zinc
PTM	Phosphoprotein Ubl conjugation
Gene Ontology (GO)
Biological process	meiosis Inferred from electronic annotation. Source: UniProtKB-KW
Molecular function	zinc ion binding Inferred from electronic annotation. Source: InterPro
Complete GO annotation...

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Chain	1 – 651	651	F-box only protein 43		PRO_0000247236
Regions
	Domain	424 – 499	76	F-box
	Zinc finger	562 – 624	63	IBR-type
Amino acid modifications
	Modified residue	33	1	Phosphoserine; by PLK1 Probable
	Modified residue	195	1	Phosphothreonine; by CaMK2 Ref.5 Ref.6
Experimental info
	Mutagenesis	32 – 33	2	DS → AA: Prevents ubiquitination and degradation in response to calcium. Ref.3 Ref.6
	Mutagenesis	194	1	S → A: Prevents ubiquitination and degradation in response to calcium. Ref.3 Ref.5 Ref.6
	Mutagenesis	195	1	T → A: Prevents ubiquitination and degradation in response to calcium. Ref.3 Ref.5 Ref.6
	Mutagenesis	283 – 284	2	DS → AA: No effect on ubiquitination and degradation in response to calcium. Ref.3 Ref.6
	Mutagenesis	336	1	T → A: No effect on ubiquitination and degradation in response to calcium. Ref.3 Ref.5 Ref.6

Sequences

	Sequence		Length	Mass (Da)
	Q8AXF4 [UniParc]. Last modified March 1, 2003. Version 1. Checksum: 48C53C789FE6491D	FASTA	651	72,303
	10 20 30 40 50 60 MANLLENFAA HHSMTAGAKK KADHQDTSVS QDSGYSDSLK GFSPDSHKSG NFLETVTEGY 70 80 90 100 110 120 ENSENIDPTL ILSPIKYELS WGADTRESKQ LAPLYETPRV GKKEFSLRRR LLISKATSGG 130 140 150 160 170 180 NLDFDVSVCS AESCGREKSL RRIPSHEGSL SNSFADSPRD GSYEPIATST LKTESESGTS 190 200 210 220 230 240 CKKWRLSFAQ QRSSTLDDSK SDSIPLPEVE NISPVQHSLA SSTDDSILYE ETIFGAPTTP 250 260 270 280 290 300 TCNFIVKEEF QTPISNLAAN FRFNLCTPDV GHVSDFDISV TEDSAFHSLS LDKSQDSITD 310 320 330 340 350 360 HEGSFQELIQ KPRETSKAVN NKSRLRKLDR CRRLSTLRER GSQSEVEEEG NEVPVLSSAY 370 380 390 400 410 420 KLKVARASVD EENEFSSDES RVHSLLSSDD LTGKPALRVL HEMLLRSTRK RPQQATVQDL 430 440 450 460 470 480 LGSSGCFELP EDSLSRLIGR KMGLETFDIL AELKNRNLKH ILASILDLVN AASICSMCRV 490 500 510 520 530 540 SRDWRDVVLQ DKSAHQRRKA YIKKLKTEAE QGRQLSFEDS ATRLNILSRS ALRSVQIQAR 550 560 570 580 590 600 SAFRTPTSSL TPGDNKSIHS ASKHQEYLKV AKTLFTDEAL KPCPRCQYPA KYQALKKRGT 610 620 630 640 650 CSRKDCGFDF CSLCLCTFHG SKECGTGSAK RIPKKEALPG SAQSKRNLKR L

References

[1]	"Identification of novel F-box proteins in Xenopus laevis." Regan-Reimann J.D., Duong Q.V., Jackson P.K. Curr. Biol. 9:R762-R763(1999) [PubMed: 10531041] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA].
[2]	"Xenopus polo-like kinase Plx1 regulates XErp1, a novel inhibitor of APC/C activity." Schmidt A., Duncan P.I., Rauh N.R., Sauer G., Fry A.M., Nigg E.A., Mayer T.U. Genes Dev. 19:502-513(2005) [PubMed: 15713843] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA], IDENTIFICATION BY MASS SPECTROMETRY, PHOSPHORYLATION, UBIQUITINATION, DEVELOPMENTAL STAGE, FUNCTION.
[3]	"A role for the anaphase-promoting complex inhibitor Emi2/XErp1, a homolog of early mitotic inhibitor 1, in cytostatic factor arrest of Xenopus eggs." Tung J.J., Hansen D.V., Ban K.H., Loktev A.V., Summers M.K., Adler J.R. III, Jackson P.K. Proc. Natl. Acad. Sci. U.S.A. 102:4318-4323(2005) [PubMed: 15753281] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA], FUNCTION, PHOSPHORYLATION AT SER-33, UBIQUITINATION, MUTAGENESIS OF 32-ASP-SER-33 AND 283-ASP-SER-284.
[4]	"Calcium elevation at fertilization coordinates phosphorylation of XErp1/Emi2 by Plx1 and CaMK II to release metaphase arrest by cytostatic factor." Liu J., Maller J.L. Curr. Biol. 15:1458-1468(2005) [PubMed: 16040245] [Abstract] Cited for: PHOSPHORYLATION.
[5]	"Calcium triggers exit from meiosis II by targeting the APC/C inhibitor XErp1 for degradation." Rauh N.R., Schmidt A., Bormann J., Nigg E.A., Mayer T.U. Nature 437:1048-1052(2005) [PubMed: 16127448] [Abstract] Cited for: PHOSPHORYLATION AT THR-195, MUTAGENESIS OF SER-194; THR-195 AND THR-336.
[6]	"CaMKII and polo-like kinase 1 sequentially phosphorylate the cytostatic factor Emi2/XErp1 to trigger its destruction and meiotic exit." Hansen D.V., Tung J.J., Jackson P.K. Proc. Natl. Acad. Sci. U.S.A. 103:608-613(2006) [PubMed: 16407128] [Abstract] Cited for: PHOSPHORYLATION AT THR-195, MUTAGENESIS OF 32-ASP-SER-33.

Cross-references

Sequence databases
EMBL GenBank DDBJ	AF176353 mRNA. Translation: AAF14554.1. Sequence problems. AF450296 mRNA. Translation: AAN76807.1. AY928267 mRNA. Translation: AAX18427.1.
RefSeq	NP_001093338.1. NM_001099868.1.
UniGene	Xl.76218.
3D structure databases
ModBase	Search...
Protein-protein interaction databases
DIP	DIP-46217N.
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Genome annotation databases
GeneID	100101275.
KEGG	xla:100101275.
Organism-specific databases
CTD	286151.
Xenbase	XB-GENE-951950. fbxo43.
Phylogenomic databases
HOVERGEN	HBG081522.
Family and domain databases
InterPro	IPR002867. Znf_C6HC. [Graphical view]
KO	K10318.
Pfam	PF01485. IBR. 1 hit. [Graphical view]
SMART	SM00647. IBR. 1 hit. [Graphical view]
PROSITE	PS50181. FBOX. False negative. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

FBX43_XENLA

Accession

Primary (citable) accession number: Q8AXF4
Secondary accession number(s): Q9PTL8

Entry history

Integrated into UniProtKB/Swiss-Prot:	July 25, 2006
Last sequence update:	March 1, 2003
Last modified:	November 16, 2011
This is version 39 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Chordata Protein Annotation Program