"Subunit of clathrin-associated adaptor protein complex 1 that plays a role in protein sorting in the late-Golgi/trans-Golgi network (TGN) and/or endosomes (PubMed:31630791)."

"The AP complexes mediate both the recruitment of clathrin to membranes and the recognition of sorting signals within the cytosolic tails of transmembrane cargo molecules."

"Adaptor protein complex 1 (AP-1) is a heterotetramer composed of two large adaptins (gamma-type subunit AP1G1 and beta-type subunit AP1B1), a medium adaptin (mu-type subunit AP1M1 or AP1M2) and a small adaptin (sigma-type subunit AP1S1 or AP1S2 or AP1S3)."

"AP1B1 encodes beta-1 adaptin, the large beta subunit of the heterotetrameric adaptor protein complex 1 (AP-1)"

"AP-1 localizes predominantly at the TGN and tubular early endosomes, consistent with a role in bidirectional TGN-endosome traffic"

"The AP-1 core comprises N-terminal fragments of the two large chains, beta1 and gamma, and the intact medium and small chains, micro1 and sigma1."

"the crystal structure of the core of the AP-1 complex, which functions in the trans-Golgi network (TGN)"

"TGN localization of AP-1 depends on the small GTPase, Arf1, and the phosphoinositide, PI-4-P."

"Packaging of the tyrosinases into transport vesicles at early/recycling endosome-associated tubules is dependent on ubiquitous adaptor protein complex (AP)-1 and AP-3"

"AP-1 and AP-3 provide alternate routes for transport of tyrosinase and possibly other cargoes to maturing melanosomes"

"endogenous Rab32 and Rab38 were found to interact with BLOC-2, AP-1 and AP-3 in membrane, but not cytosolic fractions of MNT-1 melanocyte cells"

"The GTP-dependent switch I and II regions of Arf1 bind to the N terminus of the beta1 subunit of one AP-1 complex"

"Unlocking is driven by two molecules of Arf1 that bridge two copies of AP-1 at two interaction sites."

"Arf1 activates cargo binding by unlocking AP-1."

"AP-1B facilitates basolateral sorting from REs."

"Sorting takes place at one of 2 major sorting stations in the cells, the trans-Golgi network (TGN) and recycling endosomes (REs)."

"gamma2-adaptin is capable of interacting not only with the sigma1 chain... but also with a novel sigma1-like protein... and that, unlike gamma1-adaptin, it is unable to interact with beta1-adaptin"

"gamma1-adaptin, gamma2-adaptin is capable of interacting not only with the sigma1 chain"

"The dileucine-motif-containing segment of Nef bound directly and specifically to the beta-adaptin subunit of the clathrin adaptor complexes AP-1 and AP-2"

"a mutant form of Nef that lacked the dileucine motif did not localize to clathrin-coated pits and did not downregulate CD4 expression"

"Current evidence supports a model in which AP-1 functions primarily in retrograde trafficking, retrieving proteins from post-Golgi compartments back to the TGN."

"The spatial and temporal regulation of AP-1 activity depends on a sophisticated coincidence detection mechanism involving the small GTPase Arf1 (ADP-ribosylation factor 1) and the phosphoinositide PI(4)P"

"Loss-of-function mutations in AP1B1 cause autosomal recessive keratitis-ichthyosis-deafness syndrome (KIDAR)"

"Central to the pathogenesis of both KIDAR and MEDNIK syndromes is abnormal AP-1-mediated trafficking of copper transporters."

"Affected individuals present with a constellation of features including neonatal-onset ichthyotic erythroderma, progressive sensorineural hearing loss, photophobia with corneal involvement, failure to thrive, and thrombocytopenia."

"E-cadherin localization shifted from tight junctional to diffuse cytoplasmic distribution, beta-catenin showed reduced membrane staining with cytoplasmic and nuclear accumulation"

"The human AP1B1 protein shares greater than 98% sequence identity with its canine ortholog, greater than 95% identity with chicken"

"The combinatorial expression of these isoforms generates considerable functional diversity, with humans potentially expressing up to 12 distinct AP-1 variants depending on subunit composition"

"Studies in yeast have been particularly informative: kinetic analyses using synthetic cargo revealed that AP-1 mediates active recycling of material from late-stage TGN back to earlier stages"

"AP-1A localizes predominantly to the TGN and promotes cargo exit through a direct pathway to the basolateral plasma membrane."

"The sigma1 subunit of AP-1 directly recognizes a dileucine signal in ATP7B's cytoplasmic tail, and disruption of this interaction through dominant-negative sigma1 mutants causes loss of ATP7B's polarized distribution in neurons"

"Knockout studies in mice demonstrated that targeted disruption of the mu1A-adaptin gene causes embryonic lethality at day 13.5"

"MPR46 fails to recycle from endosomes back to the TGN, providing direct evidence that AP-1 is required for retrograde receptor transport"

"Loss of AP-1 function causes mislocalization of apical proteins and the formation of ectopic microvilli-like structures in the basolateral domain"

"sequence analysis has classified adaptin HEAT repeats as a distinct subclass (ADB class) specific to the adaptor protein family"

"the beta subunits of AP-1 and AP-2 share 84% sequence identity"

"Proteomic analysis of immunocaptured AP-1 vesicles revealed they contain TGN and endosomal proteins as well as lysosomal hydrolases, but notably very little of the anterograde adaptor GGA2, strongly supporting the retrograde trafficking model"

"Recent imaging studies confirmed that nearly 100% of AP-1 vesicles are positive for clathrin"

"Protein phosphatase 2A (PP2A)-mediated dephosphorylation of beta1 enables clathrin assembly upon membrane recruitment"

"AP-1 components are exploited by viruses including SARS-CoV-2, MERS-CoV, and HIV, which selectively target the host AP-1 complex to facilitate viral entry and replication"