Page last updated: 2024-10-24

AP-2 adaptor complex

Definition

Target type: cellularcomponent

A heterotetrameric AP-type membrane coat adaptor complex that consists of alpha, beta2, mu2 and sigma2 subunits, and links clathrin to the membrane surface of a vesicle, and the cargo receptors during receptor/clathrin mediated endocytosis. Vesicles with AP-2-containing coats are normally found primarily near the plasma membrane, on endocytic vesicles. In at least humans, the AP-2 complex can be heterogeneric due to the existence of multiple subunit isoforms encoded by different alpha genes (alphaA and alphaC). [GOC:mah, PMID:10611976, PMID:21097499, PMID:22022230, PMID:24322426]

The AP-2 adaptor complex is a protein complex involved in clathrin-mediated endocytosis, a process that brings molecules from the plasma membrane into the cell. It is a heterotetrameric complex composed of two large subunits, α-adaptin and β2-adaptin, a medium subunit, μ2, and a small subunit, σ2. The complex has a characteristic structure with a "trunk" domain that binds to clathrin and a "ear" domain that interacts with cargo molecules.

The α-adaptin subunit is responsible for binding to clathrin and for interacting with the plasma membrane. It has a clathrin-binding domain and a phosphoinositide-binding domain that allows it to bind to the membrane. The β2-adaptin subunit is responsible for binding to cargo molecules and for interacting with the μ2 subunit. It has a "trunk" domain that interacts with the μ2 subunit and an "ear" domain that binds to cargo molecules.

The μ2 subunit acts as a bridge between the α-adaptin and β2-adaptin subunits. It has a tyrosine-based sorting signal that allows it to interact with cargo molecules. The σ2 subunit is a small, regulatory subunit that plays a role in the assembly and disassembly of the AP-2 complex.

The cellular component of the AP-2 complex can be localized to the plasma membrane, where it participates in the formation of clathrin-coated pits, or in the cytoplasm, where it is involved in the assembly and disassembly of the complex. The specific location of the AP-2 complex within the cell is influenced by various factors, including the presence of cargo molecules and the phosphorylation state of the complex.

The AP-2 complex is essential for the proper functioning of many cellular processes, including signal transduction, cell migration, and nutrient uptake. Dysregulation of AP-2 complex function has been implicated in several human diseases, such as cancer and neurodegenerative disorders. In summary, the AP-2 adaptor complex plays a crucial role in clathrin-mediated endocytosis, a fundamental cellular process responsible for the internalization of various molecules from the plasma membrane.'
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Proteins (1)

ProteinDefinitionTaxonomy
Vesicular acetylcholine transporterA vesicular acetylcholine transporter that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q16572]Homo sapiens (human)

Compounds (5)

CompoundDefinitionClassesRoles
vesamicolvesamicol: RN given refers to parent cpd; structurepiperidines
hemicholinium 3Hemicholinium 3: A potent inhibitor of the high affinity uptake system for CHOLINE. It has less effect on the low affinity uptake system. Since choline is one of the components of ACETYLCHOLINE, treatment with hemicholinium can deplete acetylcholine from cholinergic terminals. Hemicholinium 3 is commonly used as a research tool in animal and in vitro experiments.
4-phenylpiperidine
vesamicolpiperidines
benzovesamicolbenzovesamicol: structure in first source