AP2A2 - AP-2 complex subunit alpha-2 - human protein (Function)
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AP2A2 »  AP-2 complex subunit alpha-2
Protein also known as:  Plasma membrane adaptor HA2/AP2 adaptin alpha C subunit.
Gene name:  AP2A2
Entry whose protein(s) existence is based on evidence at protein level
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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 surrounded 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 alpha subunit binds polyphosphoinositide-containing lipids, positioning AP-2 on the membrane. The AP-2 alpha subunit acts via its C-terminal appendage domain as a scaffolding platform for endocytic accessory proteins. The AP-2 alpha and AP-2 sigma subunits are thought to contribute to the recognition of the [ED]-X-X-X-L-[LI] motif (By similarity).  
  • UniProtKB
GO molecular function 
Contributes to clathrin adaptor activitydefinition[GO:0035615]  
Lipid bindingdefinition[GO:0008289]  
  • UniProtKB KW
Protein bindingdefinition[GO:0005515]  
  • IntAct
Protein complex bindingdefinition[GO:0032403] silver  
  • Ortholog Compara
Protein kinase bindingdefinition[GO:0019901]  
  • Ortholog Curator
Protein transporter activitydefinition[GO:0008565] silver  
  • InterPro 2 GO
GO biological process 
Clathrin-mediated endocytosisdefinition[GO:0072583]  
Intracellular protein transportdefinition[GO:0006886] silver  
  • InterPro 2 GO
According to KEGG, this protein belongs to the following pathways:
Endocrine and other factor-regulated calcium reabsorption  hsa04961+161  
Endocytosis  hsa04144+161  
Huntington's disease  hsa05016+161  
Synaptic vesicle cycle  hsa04721+161  
According to Reactome, this protein belongs to the following pathways:
EGFR downregulation  R-HSA-182971  
EPH-ephrin mediated repulsion of cells  R-HSA-3928665  
MHC class II antigen presentation  R-HSA-2132295  
Nef Mediated CD4 Down-regulation  R-HSA-167590  
Nef Mediated CD8 Down-regulation  R-HSA-182218  
Recycling pathway of L1  R-HSA-437239  
Retrograde neurotrophin signalling  R-HSA-177504  
Trafficking of GluR2-containing AMPA receptors  R-HSA-416993  
WNT5A-dependent internalization of FZD4  R-HSA-5099900  


Biological process 
Endocytosis  definition   [KW-0254]
Protein transport  definition   [KW-0653]
Transport  definition   [KW-0813]
Technical term 
Reference proteome  definition   [KW-1185]

Further external links

GeneWiki: AP2A2
GenomeRNAi: 161
PRO: PR:O94973