Reviewed, UniProtKB/Swiss-Prot P84092 (AP2M1_RAT)

Names and origin

Protein names

Recommended name:
    AP-2 complex subunit mu
Alternative name(s):
    Adapter-related protein complex 2 mu subunit
    Adaptor protein complex AP-2 subunit mu
    Mu2-adaptin
    AP-2 mu chain
    Plasma membrane adaptor AP-2 50 kDa protein
    Clathrin assembly protein complex 2 medium chain
    Clathrin coat assembly protein AP50
    Clathrin coat-associated protein AP50

Gene names

Name:

Ap2m1

Organism

Rattus norvegicus (Rat)

Taxonomic identifier

10116 [NCBI]

Taxonomic lineage

Eukaryota › Metazoa › Chordata › Craniata › Vertebrata › Euteleostomi › Mammalia › Eutheria › Euarchontoglires › Glires › Rodentia › Sciurognathi › Muroidea › Muridae › Murinae › Rattus

Protein attributes

Sequence length	435 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is not processed.
Protein existence	Evidence at protein level.

General annotation (Comments)

Function	Component of the adaptor protein complex 2 (AP-2). Adaptor protein complexes function in protein transport via Transport vesicles in different membrane traffic pathways. Adaptor protein complexes are vesicle coat components and appear to be involved in cargo selection and vesicle formation. AP-2 is involved in clathrin-dependent endocytosis in which cargo proteins are incorporated into vesicles surrrounded by clathrin (clathrin-coated vesicles, CCVs) which are destined for fusion with the early endosome. The clathrin lattice serves as a mechanical scaffold but is itself unable to bind directly to membrane components. Clathrin-associated adaptor protein (AP) complexes which can bind directly to both the clathrin lattice and to the lipid and protein components of membranes are considered to be the major clathrin adaptors contributing the CCV formation. AP-2 also serves as a cargo receptor to selectively sort the membrane proteins involved in receptor-mediated endocytosis. AP-2 seems to play a role in the recycling of synaptic vesicle membranes from the presynaptic surface. AP-2 recognizes Y-X-X-[FILMV] (Y-X-X-Phi) and [ED]-X-X-X-L-[LI] endocytosis signal motifs within the cytosolic tails of transmembrane cargo molecules. AP-2 may also play a role in maintaining normal post-endocytic trafficking through the ARF6-regulated, non-clathrin pathway. The AP-2 mu subunit binds to transmembrane cargo proteins; it recognizes the Y-X-X-Phi motifs. The surface region interacting with to the Y-X-X-Phi motif is inaccessible in cytosolic AP-2, but becomes accessible through a conformational change following phosphorylation of AP-2 mu subunit at 'Tyr-156' in membrane-associated AP-2. The membrane-specific phosphorylation event appears to involve assembled clathrin which activates the AP-2 mu kinase AAK1 By similarity.
Subunit structure	Adaptor protein complex 2 (AP-2) is an heterotetramer composed of two large adaptins (alpha-type subunit AP2A1 or AP2A2 and beta-type subunit AP2B1), a medium adaptin (mu-type subuni AP2M1) and a small adaptin (sigma-type subunit AP2S1). Interacts with ATP6V1H and MEGF10. Interacts with EGFR and TTGN1. Interacts with F2R. Interacts with PIP5K1C isoform 1; tyrosine phosphorylation of PIP5K1C weakens the interaction By similarity.
Subcellular location	Cell membrane By similarity. Membrane › coated pit; Peripheral membrane protein; Cytoplasmic side By similarity. Note: AP-2 appears to be excluded from internalizing CCVs and to disengage from sites of endocytosis seconds before internalization of the nascent CCV By similarity.
Tissue specificity	Detected in brain.
Post-translational modification	Phosphorylated By similarity.
Sequence similarities	Belongs to the adaptor complexes medium subunit family. Contains 1 MHD (mu homology) domain.

Ontologies

Keywords
Biological process	Protein transport Transport
Cellular component	Cell membrane Coated pit Membrane
Ligand	Lipid-binding
PTM	Phosphoprotein
Technical term	3D-structure
Gene Ontology (GO)
Biological process	intracellular protein transport Inferred from electronic annotation. Source: InterPro vesicle-mediated transport Ref.1 Traceable author statement. Source: RGD
Cellular component	clathrin adaptor complex Inferred from electronic annotation. Source: InterPro clathrin coat of coated pit Inferred from electronic annotation. Source: InterPro clathrin vesicle coat Ref.1 Traceable author statement. Source: RGD transport vesicle Ref.1 Traceable author statement. Source: RGD
Molecular function	lipid binding Inferred from electronic annotation. Source: UniProtKB-KW protein binding Inferred from sequence or structural similarity. Source: UniProtKB
Complete GO annotation...

Binary interactions

With	Entry	#Exp.	IntAct	Notes
Ston1	Q8CDJ8	1	EBI-297693,EBI-539420	From a different organism.
Ston2	Q8BZ60	1	EBI-297693,EBI-539385	From a different organism.
Ttgn1	P19814	4	EBI-297693,EBI-541446

Sequence annotation (Features)

Feature key

Position(s)

Length

Description

Graphical view

Feature identifier

Molecule processing

Chain

1 – 435

435

AP-2 complex subunit mu

PRO_0000193776

Regions

Domain

167 – 435

269

MHD

Sites

Binding site

341

1

Phosphatidylinositol lipid headgroup

Binding site

343

1

Phosphatidylinositol lipid headgroup

Binding site

345

1

Phosphatidylinositol lipid headgroup

Binding site

354

1

Phosphatidylinositol lipid headgroup

Binding site

356

1

Phosphatidylinositol lipid headgroup

Amino acid modifications

Modified residue

45

1

Phosphoserine By similarity

Modified residue

156

1

Phosphothreonine By similarity

Experimental info

Mutagenesis

156

1

T → A: Inhibits endocytosis by AP-2; no effect on membrane association of AP-2. Ref.4

Mutagenesis

176

1

D → A: Abolishes interaction with TTGN1 and EGFR. Ref.3

Mutagenesis

421

1

W → A: Abolishes interaction with TTGN1 and EGFR. Ref.3

Secondary structure

1

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435

Helix Strand Turn

Details...

Beta strand

4 – 8

5

Beta strand

14 – 19

6

Beta strand

21 – 23

3

Helix

26 – 35

10

Turn

36 – 38

3

Beta strand

46 – 50

5

Beta strand

53 – 60

8

Beta strand

63 – 71

9

Helix

75 – 93

19

Helix

98 – 103

6

Helix

105 – 115

11

Beta strand

172 – 185

14

Beta strand

191 – 205

15

Beta strand

207 – 209

3

Beta strand

211 – 217

7

Beta strand

244 – 248

5

Beta strand

263 – 265

3

Beta strand

269 – 279

11

Beta strand

286 – 296

11

Turn

297 – 299

3

Beta strand

300 – 309

10

Beta strand

315 – 325

11

Beta strand

330 – 345

16

Turn

346 – 349

4

Beta strand

350 – 361

12

Beta strand

363 – 372

10

Beta strand

386 – 394

9

Beta strand

401 – 407

7

Beta strand

409 – 412

4

Helix

415 – 417

3

Beta strand

418 – 433

16

Sequences

	Sequence		Length	Mass (Da)
	P84092-1 [UniParc]. Last modified August 16, 2004. Version 1. Checksum: 82803219BA279954	FASTA	435	49,655
	10 20 30 40 50 60 MIGGLFIYNH KGEVLISRVY RDDIGRNAVD AFRVNVIHAR QQVRSPVTNI ARTSFFHVKR 70 80 90 100 110 120 SNIWLAAVTK QNVNAAMVFE FLYKMCDVMA AYFGKISEEN IKNNFVLIYE LLDEILDFGY 130 140 150 160 170 180 PQNSETGALK TFITQQGIKS QHQTKEEQSQ ITSQVTGQIG WRREGIKYRR NELFLDVLES 190 200 210 220 230 240 VNLLMSPQGQ VLSAHVSGRV VMKSYLSGMP ECKFGMNDKI VIEKQGKGTA DETSKSGKQS 250 260 270 280 290 300 IAIDDCTFHQ CVRLSKFDSE RSISFIPPDG EFELMRYRTT KDIILPFRVI PLVREVGRTK 310 320 330 340 350 360 LEVKVVIKSN FKPSLLAQKI EVRIPTPLNT SGVQVICMKG KAKYKASENA IVWKIKRMAG 370 380 390 400 410 420 MKESQISAEI ELLPTNDKKK WARPPISMNF EVPFAPSGLK VRYLKVFEPK LNYSDHDVIK 430 WVRYIGRSGI YETRC

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"Molecular cloning and complete amino acid sequence of AP50, an assembly protein associated with clathrin-coated vesicles." Thurieau C., Brosius J., Burne C., Jolles P., Keen J.H., Mattaliano R.J., Chow E.P., Ramachandran K.L., Kirchhausen T. DNA 7:663-669(1988) [PubMed: 3148444] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA]. Tissue: Brain.
[2]	"The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC)." The MGC Project Team Genome Res. 14:2121-2127(2004) [PubMed: 15489334] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA]. Tissue: Brain.
[3]	"Inhibition of the receptor-binding function of clathrin adaptor protein AP-2 by dominant-negative mutant mu2 subunit and its effects on endocytosis." Nesterov A., Carter R.E., Sorkina T., Gill G.N., Sorkin A. EMBO J. 18:2489-2499(1999) [PubMed: 10228163] [Abstract] Cited for: INTERACTION WITH EGFR AND TTGN1, MUTAGENESIS OF ASP-176 AND TRP-421.
[4]	"Phosphorylation of threonine 156 of the mu2 subunit of the AP2 complex is essential for endocytosis in vitro and in vivo." Olusanya O., Andrews P.D., Swedlow J.R., Smythe E. Curr. Biol. 11:896-900(2001) [PubMed: 11516654] [Abstract] Cited for: FUNCTION OF THE AP-2 COMPLEX, MUTAGENESIS OF THR-156.
[5]	"Adaptor protein complexes as the key regulators of protein sorting in the post-Golgi network." Nakatsu F., Ohno H. Cell Struct. Funct. 28:419-429(2003) [PubMed: 14745134] [Abstract] Cited for: FUNCTION OF THE AP-2 COMPLEX IN CLATHRIN-MEDIATED ENDOCYTOSIS.
[6]	"Adaptors for clathrin coats: structure and function." Owen D.J., Collins B.M., Evans P.R. Annu. Rev. Cell Dev. Biol. 20:153-191(2004) [PubMed: 15473838] [Abstract] Cited for: FUNCTION OF THE AP-2 COMPLEX IN CLATHRIN-MEDIATED ENDOCYTOSIS.
[7]	"A structural explanation for the recognition of tyrosine-based endocytotic signals." Owen D.J., Evans P.R. Science 282:1327-1332(1998) [PubMed: 9812899] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (2.65 ANGSTROMS) OF 159-435 IN COMPLEX WITH EGFR INTERNALIZATION SIGNAL.
[8]	"A third specificity-determining site in mu 2 adaptin for sequences upstream of Yxx phi sorting motifs." Owen D.J., Setiadi H., Evans P.R., McEver R.P., Green S.A. Traffic 2:105-110(2001) [PubMed: 11247301] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (3 ANGSTROMS) OF 158-435 IN COMPLEX WITH SELP INTERNALIZATION SIGNAL.
[9]	"Molecular architecture and functional model of the endocytic AP2 complex." Collins B.M., McCoy A.J., Kent H.M., Evans P.R., Owen D.J. Cell 109:523-535(2002) [PubMed: 12086608] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (2.59 ANGSTROMS) IN COMPLEX WITH AP2B1; AP2A2; AP2S1 AND AN INOSITOL POLYPHOSPHATE HEADGROUP.
[10]	"The mu2 subunit of the clathrin adaptor AP-2 binds to FDNPVY and YppO sorting signals at distinct sites." Boll W., Rapoport I., Brunner C., Modis Y., Prehn S., Kirchhausen T. Traffic 3:590-600(2002) [PubMed: 12121421] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (2.5 ANGSTROMS) OF 260-435 IN COMPLEX WITH EGFR INTERNALIZATION SIGNAL.
[11]	"A structural explanation for the binding of endocytic dileucine motifs by the AP2 complex." Kelly B.T., McCoy A.J., Spaete K., Miller S.E., Evans P.R., Hoening S., Owen D.J. Nature 456:976-979(2008) [PubMed: 18978775] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (1.60 ANGSTROMS) OF 1-435 IN COMPLEX WITH AP2A2; AP2B1; AP2S1 AND CD4 INTERNALIZATION SIGNAL.
+	Additional computationally mapped references.

Cross-references

Sequence databases

EMBLGenBankDDBJ

M23674 mRNA. Translation: AAA72731.1.
BC087724 mRNA. Translation: AAH87724.1.

IPI

IPI00196530.

PIR

A31596.

RefSeq

NP_446289.1.

UniGene

Rn.3172

3D structure databases

PDBPDBe

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1BW8	X-ray	2.65	A	122-435	[»]
1BXX	X-ray	2.70	A	158-435	[»]
1HES	X-ray	3.00	A	158-435	[»]
1I31	X-ray	2.50	A	122-435	[»]
2BP5	X-ray	2.80	M	1-435	[»]
2JKR	X-ray	2.98	M/U	1-435	[»]
2JKT	X-ray	3.40	M/U	1-435	[»]
2PR9	X-ray	2.51	A	158-435	[»]
2VGL	X-ray	2.59	M	1-435	[»]

DisProt

DP00455.

ModBase

Search...

Protein-protein interaction databases

IntAct

P84092. 11 interactions.

STRING

P84092.

PTM databases

PhosphoSite

P84092.

Proteomic databases

PRIDE

P84092.

Genome annotation databases

Ensembl

ENSRNOT00000002325; ENSRNOP00000002325; ENSRNOG00000001709; Rattus norvegicus. [Genome view]

GeneID

116563.

KEGG

rno:116563.

UCSC

NM_053837. rat.

Organism-specific databases

CTD

116563.

RGD

620135. Ap2m1.

Phylogenomic databases

HOVERGEN

P84092.

OMA

KNEAFVD

Gene expression databases

ArrayExpress

P84092.

Genevestigator

P84092.

GermOnline

ENSRNOG00000001709. Rattus norvegicus.

Family and domain databases

InterPro

IPR015629. Clathrin_AP50.
IPR001392. Clathrin_mu.
IPR008968. Clathrin_mu_C.
IPR018240. Clathrin_mu_CS.
IPR011012. Longin-like.
[Graphical view]

PANTHER

PTHR11998:SF12. Clathrin_coat_assem_AP50. 1 hit.

Pfam

PF00928. Adap_comp_sub. 1 hit.
[Graphical view]

PIRSF

PIRSF005992. Clathrin_mu. 1 hit.

PRINTS

PR00314. CLATHRINADPT.

PROSITE

PS00990. CLAT_ADAPTOR_M_1. 1 hit.
PS00991. CLAT_ADAPTOR_M_2. 1 hit.
PS51072. MHD. 1 hit.
[Graphical view]

ProtoNet

Search...

Other Resources

NextBio

619237.

Entry information

Entry name

AP2M1_RAT

Accession

Primary (citable) accession number: P84092
Secondary accession number(s): P20172, P53679

Entry history

Integrated into UniProtKB/Swiss-Prot:	August 16, 2004
Last sequence update:	August 16, 2004
Last modified:	November 24, 2009
This is version 59 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

HPI (Human Proteome Initiative)