CPLM-000095

Genbank Nucleotide ID

Importin subunit alpha-4

Protein Synonyms/Alias

Importin alpha Q2; Qip2; Karyopherin subunit alpha-3; SRP1-gamma

Homo sapiens (Human)

Position	Peptide	Type	References
97	SAVQAARKLLSSDRN	ubiquitination	[1]
121	GILPILVKCLERDDN	ubiquitination	[2, 3]
386	KGDFGTQKEAAWAIS	ubiquitination	[1, 2, 3]

[1] A proteome-wide, quantitative survey of in vivo ubiquitylation sites reveals widespread regulatory roles.
Wagner SA, Beli P, Weinert BT, Nielsen ML, Cox J, Mann M, Choudhary C.
Mol Cell Proteomics. 2011 Oct;10(10):M111.013284. [PMID: 21890473]
[2] Refined preparation and use of anti-diglycine remnant (K-ε-GG) antibody enables routine quantification of 10,000s of ubiquitination sites in single proteomics experiments.
Udeshi ND, Svinkina T, Mertins P, Kuhn E, Mani DR, Qiao JW, Carr SA.
Mol Cell Proteomics. 2013 Mar;12(3):825-31. [PMID: 23266961]
[3] Integrated proteomic analysis of post-translational modifications by serial enrichment.
Mertins P, Qiao JW, Patel J, Udeshi ND, Clauser KR, Mani DR, Burgess MW, Gillette MA, Jaffe JD, Carr SA.
Nat Methods. 2013 Jul;10(7):634-7. [PMID: 23749302]

Functional Description

Functions in nuclear protein import as an adapter protein for nuclear receptor KPNB1. Binds specifically and directly to substrates containing either a simple or bipartite NLS motif. Docking of the importin/substrate complex to the nuclear pore complex (NPC) is mediated by KPNB1 through binding to nucleoporin FxFG repeats and the complex is subsequently translocated through the pore by an energy requiring, Ran- dependent mechanism. At the nucleoplasmic side of the NPC, Ran binds to importin-beta and the three components separate and importin-alpha and -beta are re-exported from the nucleus to the cytoplasm where GTP hydrolysis releases Ran from importin. The directionality of nuclear import is thought to be conferred by an asymmetric distribution of the GTP- and GDP-bound forms of Ran between the cytoplasm and nucleus. In vitro, mediates the nuclear import of human cytomegalovirus UL84 by recognizing a non- classical NLS. Recognizes NLSs of influenza A virus nucleoprotein probably through ARM repeats 7-9.

DOMAIN 2 58 IBB.
REPEAT 66 106 ARM 1; truncated.
REPEAT 107 149 ARM 2.
REPEAT 150 194 ARM 3.
REPEAT 195 233 ARM 4.
REPEAT 234 278 ARM 5.
REPEAT 279 318 ARM 6.
REPEAT 319 360 ARM 7.
REPEAT 361 400 ARM 8.
REPEAT 401 443 ARM 9.
REPEAT 447 485 ARM 10; atypical.
REGION 137 229 NLS binding site (major) (By similarity).
REGION 306 394 NLS binding site (minor) (By similarity).
MOTIF 43 52 Nuclear localization signal (By
MOD_RES 2 2 N-acetylalanine.
MOD_RES 56 56 Phosphoserine.
MOD_RES 60 60 Phosphoserine.

Acetylation; Complete proteome; Cytoplasm; Host-virus interaction; Nucleus; Phosphoprotein; Polymorphism; Protein transport; Reference proteome; Repeat; Transport; Viral penetration into host nucleus; Virus entry into host cell.

UniProt (SWISSPROT/TrEMBL); GenBank; EMBL

GO:0005829; C:cytosol; TAS:Reactome.
GO:0005643; C:nuclear pore; TAS:ProtInc.
GO:0005654; C:nucleoplasm; TAS:Reactome.
GO:0008139; F:nuclear localization sequence binding; TAS:ProtInc.
GO:0008565; F:protein transporter activity; IEA:InterPro.
GO:0019221; P:cytokine-mediated signaling pathway; TAS:Reactome.
GO:0006607; P:NLS-bearing substrate import into nucleus; TAS:ProtInc.
GO:0006461; P:protein complex assembly; TAS:ProtInc.
GO:0046718; P:viral entry into host cell; IEA:UniProtKB-KW.
GO:0075732; P:viral penetration into host nucleus; IEA:UniProtKB-KW.

IPR011989; ARM-like.
IPR016024; ARM-type_fold.
IPR000225; Armadillo.
IPR002652; Importin-a_IBB.
IPR024931; Importing_su_alpha.

PF00514; Arm
PF01749; IBB

PS50176; ARM_REPEAT
PS51214; IBB