AP-2 complex subunit beta (AP2B1)
The protein contains 937 amino acids for an estimated molecular weight of 104553 Da.
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. During long-term potentiation in hippocampal neurons, AP-2 is responsible for the endocytosis of ADAM10 (PubMed:23676497). The AP-2 beta (updated: July 31, 2019)
Protein identification was indicated in the following studies:
- Goodman and co-workers. (2013) The proteomics and interactomics of human erythrocytes. Exp Biol Med (Maywood) 238(5), 509-518.
- Lange and co-workers. (2014) Annotating N termini for the human proteome project: N termini and Nα-acetylation status differentiate stable cleaved protein species from degradation remnants in the human erythrocyte proteome. J Proteome Res. 13(4), 2028-2044.
- Hegedűs and co-workers. (2015) Inconsistencies in the red blood cell membrane proteome analysis: generation of a database for research and diagnostic applications. Database (Oxford) 1-8.
- Wilson and co-workers. (2016) Comparison of the Proteome of Adult and Cord Erythroid Cells, and Changes in the Proteome Following Reticulocyte Maturation. Mol Cell Proteomics. 15(6), 1938-1946.
- Bryk and co-workers. (2017) Quantitative Analysis of Human Red Blood Cell Proteome. J Proteome Res. 16(8), 2752-2761.
- D'Alessandro and co-workers. (2017) Red blood cell proteomics update: is there more to discover? Blood Transfus. 15(2), 182-187.
- Chu and co-workers. (2018) Quantitative mass spectrometry of human reticulocytes reveal proteome-wide modifications during maturation. Br J Haematol. 180(1), 118-133.
Methods
The following articles were analysed to gather the proteome content of erythrocytes.
The gene or protein list provided in the studies were processed using the ID mapping API of Uniprot in September 2018. The number of proteins identified and mapped without ambiguity in these studies is indicated below.
Only Swiss-Prot entries (reviewed) were considered for protein evidence assignation.
| Publication | Identification 1 | Uniprot mapping 2 | Not mapped / Obsolete | TrEMBL | Swiss-Prot |
|---|---|---|---|---|---|
| Goodman (2013) | 2289 (gene list) | 2278 | 53 | 20599 | 2269 |
| Lange (2014) | 1234 | 1234 | 7 | 28 | 1224 |
| Hegedus (2015) | 2638 | 2622 | 0 | 235 | 2387 |
| Wilson (2016) | 1658 | 1528 | 170 | 291 | 1068 |
| d'Alessandro (2017) | 1826 | 1817 | 2 | 0 | 1815 |
| Bryk (2017) | 2090 | 2060 | 10 | 108 | 1942 |
| Chu (2018) | 1853 | 1804 | 55 | 362 | 1387 |
1 as available in the article and/or in supplementary material
2 uniprot mapping returns all protein isoforms as one entry
The compilation of older studies can be retrieved from the Red Blood Cell Collection database.
The data and differentiation stages presented below come from the proteomic study and analysis performed by our partners of the GReX consortium, more details are available in their published work.
This protein is annotated as membranous in Gene Ontology, is annotated as membranous in UniProt.
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Biological Process
Antigen processing and presentation of exogenous peptide antigen via MHC class II
Aorta development
Axon guidance
Chemical synaptic transmission
Clathrin coat assembly
Clathrin-dependent endocytosis
Coronary vasculature development
Ephrin receptor signaling pathway
Epidermal growth factor receptor signaling pathway
Intracellular protein transport
Kidney development
Low-density lipoprotein particle clearance
Low-density lipoprotein particle receptor catabolic process
Membrane organization
Microtubule-based movement
Negative regulation of epidermal growth factor receptor signaling pathway
Negative regulation of neuron death
Neurotransmitter receptor internalization
Neurotrophin TRK receptor signaling pathway
Positive regulation of endocytosis
Positive regulation of protein localization to membrane
Postsynaptic neurotransmitter receptor internalization
Regulation of defense response to virus by virus
Synaptic vesicle endocytosis
Ventricular septum development
Vesicle-mediated transport
Viral process
Wnt signaling pathway, planar cell polarity pathway
Cellular Component
AP-2 adaptor complex
Clathrin adaptor complex
Clathrin-coated endocytic vesicle
Clathrin-coated endocytic vesicle membrane
Cytosol
Endocytic vesicle membrane
Endolysosome membrane
Glutamatergic synapse
Intracellular membrane-bounded organelle
Membrane
Plasma membrane
Postsynapse
Presynapse
Trans-Golgi network
The reference OMIM entry for this protein is 601025
Adaptor-related protein complex 2, beta-1 subunit; ap2b1
Clathrin-associated/assembly/adaptor protein, large, beta-1; clapb1
Clathrin adaptor complex ap2, beta subunit
Ap2-beta
Adaptin, beta-2
DESCRIPTION
The AP2B1 protein is part of the AP2 coat assembly protein complex (see 601024) and links clathrin (118960) to receptors in the coated vesicles (summary by Ponnambalam et al., 1990).CLONING
The beta adaptin subunit of the clathrin coat assembly complex, also referred to as AP2-beta, was cloned from human, rat and bovine cDNA libraries by Ponnambalam et al. (1990), who found that the predicted 937-amino acid proteins are totally conserved between species.BIOCHEMICAL FEATURES
- Crystal Structure Kelly et al. (2014) determined a structure of AP2 that includes the clathrin-binding beta-2 hinge and developed an AP2-dependent budding assay. The authors found that an autoinhibitory mechanism prevents clathrin recruitment by cytosolic AP2. A large-scale conformational change driven by the plasma membrane phosphoinositide phosphatidylinositol 4,5-bisphosphate and cargo relieves this autoinhibition, triggering clathrin recruitment and hence clathrin-coated bud formation. Kelly et al. (2014) concluded that this molecular switching mechanism can couple AP2's membrane recruitment to its key functions of cargo and clathrin binding.MAPPING
Druck et al. (1995) used a probe from the 3-prime UTR of the human cDNA to map the gene to chromosome 17. Hybrids with portions of chromosome 17 were then used to localize CLAPB1 to 17q11.2-q12. ... More on the omim web site
Aug. 19, 2019: Protein entry updated
Automatic update: Entry updated from uniprot information.
May 12, 2019: Protein entry updated
Automatic update: model status changed
Nov. 16, 2018: Protein entry updated
Automatic update: model status changed
Feb. 2, 2018: Protein entry updated
Automatic update: Uniprot description updated
Dec. 19, 2017: Protein entry updated
Automatic update: Uniprot description updated
Nov. 23, 2017: Protein entry updated
Automatic update: Uniprot description updated
Oct. 26, 2017: Protein entry updated
Automatic update: model status changed
March 16, 2016: Protein entry updated
Automatic update: OMIM entry 601025 was added.
Jan. 24, 2016: Protein entry updated
Automatic update: model status changed