Gene Ontology annotation through association of InterPro records with GO terms
Gene Ontology annotation based on Enzyme Commission mapping
Manual transfer of experimentally-verified manual GO annotation data to orthologs by curator judgment of sequence similarity
Annotation inferences using phylogenetic trees
Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt
Gene Ontology annotation based on curation of immunofluorescence data
Automatic Gene Ontology annotation based on Rhea mapping
Phosphorylation of the AP2 mu subunit by AAK1 mediates high affinity binding to membrane protein sorting signals.
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AAK1 is the endogenous candidate kinase for AP2M1/μ2 Thr156.
"Together, these data suggest that AAK1 corresponds to the endogenous kinase responsible for phosphorylation of μ2 at Thr-156."
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AAK1 phosphorylation of AP2M1/μ2 increases AP2 affinity for cargo sorting signals.
"Thus, our in vitro experiments demonstrate that AP2 affinity for sorting signals can be significantly regulated by AAK1-mediated phosphorylation of μ2."
Identification of an adaptor-associated kinase, AAK1, as a regulator of clathrin-mediated endocytosis.
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AAK1 directly binds the AP2 α-adaptin subunit in vitro.
"Thus, these results demonstrate that AAK1 interacts directly with α-adaptin in vitro."
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AAK1 preferentially phosphorylates μ subunits of AP complexes.
"These results provide strong evidence that μ is a specific target of AAK1 phosphorylation in CCVs and suggests that the observed phosphorylation of μ can be attributed to the presence of endogenous AAK1 in these samples (Fig. 4)."
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AAK1 regulates an early AP2-dependent step of clathrin-mediated endocytosis.
"Collectively, these data provide functional evidence that AAK1 plays a role in AP2-stimulated endocytosis at an early step by specifically phosphorylating the μ subunit of the AP complex."
Differential requirements for AP-2 in clathrin-mediated endocytosis.
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Efficient AP2 recruitment and μ2 phosphorylation require AAK1's α-adaptin-interacting domain.
"We conclude that efficient recruitment of AAK1 to AP-2 and its phosphorylation of μ2 requires the AID and that each of the individual domains and truncated mutants retain their expected activities."
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Full-length AAK1 overexpression binds and disrupts AP2 function in human cells.
"These data establish that AAK1 can bind to and disrupt the function of AP-2 complexes in vivo."
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Approximately 80% AAK1 knockdown did not measurably change transferrin uptake, AP2 distribution, or μ2 phosphorylation in A549 or HeLa cells.
"Transfection of two different siRNAs that specifically target AAK1 reduced AAK1 expression by ∼80% in either A549 or HeLa cells. However, in neither case did we observe an alteration in Tfn internalization, AP-2 distribution, or μ2 phosphorylation (Fig. S2, available at http://www.jcb.org/cgi/content/full/jcb.200304069/DC1)."
AAK1-mediated micro2 phosphorylation is stimulated by assembled clathrin.
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Clathrin stimulates AAK1-dependent AP2 μ2 phosphorylation.
"Here, we report that AAK1 is an atypical kinase that is rate limited by its stable association with AP2 and that clathrin stimulates micro2 phosphorylation by AAK1."
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Assembled clathrin cages stimulate AAK1 more strongly than unassembled triskelia.
"Importantly, incubation of AAK1 with clathrin cages resulted in even greater stimulation when compared to that of unassembled clathrin triskelia."
A novel AAK1 splice variant functions at multiple steps of the endocytic pathway.
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The long AAK1 isoform has an extended C terminus with a second, directly clathrin-binding domain.
"Here we have identified a long form of AAK1 (AAK1L) that contains an extended C-terminus that encodes an additional clathrin-binding domain (CBD2) consisting of multiple low-affinity interaction motifs. Protein interaction studies demonstrate that AAK1L CBD2 directly binds clathrin."
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The long and short AAK1 isoforms show similar basal and clathrin-stimulated kinase activity toward AP2 μ2 in vitro.
"However, in vitro kinase assays reveal little difference between AAK1 isoforms in their basal or clathrin-stimulated kinase activity toward the AP-2 micro2 subunit."
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AAK1 depletion impairs transferrin recycling from early/sorting endosomes, supporting an endosomal recycling role in addition to internalization.
"Surprisingly, CBD2 overexpression or AAK1 depletion by RNA interference significantly impairs transferrin recycling from the early/sorting endosome."
AAK1 regulates Numb function at an early step in clathrin-mediated endocytosis.
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The paper reports AAK1-dependent redistribution of Numb between perinuclear endosomes and the plasma membrane; this localization phenotype remains usable with overexpression/depletion caveats.
"We find that AAK1 redistributes Numb to perinuclear endosomes when overexpressed, while kinase depletion causes Numb to accumulate at the plasma membrane."
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The paper reports Numb Thr102 as an AAK1 phosphorylation site, but that substrate/site assignment is disputed by PMID:42082516.
"Overexpression of a Numb point mutant (T102A) that lacks the AAK1 phosphorylation site potently disrupts transferrin and low-density lipoprotein internalization but does not impact EGF uptake."
The adaptor-associated kinase 1, AAK1, is a positive regulator of the Notch pathway.
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AAK1 directly interacts with the membrane-tethered activated form of Notch.
"We show here that AAK1, the adaptor-associated kinase 1, directly interacts with the membrane-tethered active form of Notch released by metalloprotease cleavage."
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Active AAK1 stabilizes activated and monoubiquitinated Notch upstream of γ-secretase cleavage.
"Active AAK1 acts upstream of the γ-secretase cleavage by stabilizing both the membrane-tethered activated form of Notch and its monoubiquitinated counterpart."
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AAK1 promotes activated Notch localization to Rab5-positive endosomes, whereas AAK1 depletion interferes with that localization.
"Moreover, transfected AAK1 increases the localization of activated Notch to Rab5-positive endocytic vesicles, while AAK1 depletion or overexpression of Numb, an inhibitor of the pathway, interferes with this localization."
Identification of novel ATP13A2 interactors and their role in α-synuclein misfolding and toxicity.
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A membrane yeast-two-hybrid screen reported 43 ATP13A2 interactors, but the cached abstract does not identify AAK1 among them.
"Utilizing a split-ubiquitin membrane yeast two-hybrid system that was developed to identify interacting partners of full-length integral membrane proteins, we identified 43 novel interactors that primarily implicate ATP13A2 in cellular processes such as endoplasmic reticulum (ER) translocation, ER-to-Golgi trafficking and vesicular transport and fusion."
Αvβ3-integrin-mediated adhesion is regulated through an AAK1L- and EHD3-dependent rapid-recycling pathway.
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AAK1L and EHD3 are required for αvβ3-integrin-mediated adhesion in human HeLa cells.
"We discovered that two early endosome factors, AAK1L and EHD3, are critical for αvβ3-integrin-mediated cell adhesion in HeLa cells."
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Depletion of either AAK1L or EHD3 delays short-loop β3-integrin recycling from early endosomes to the cell surface.
"siRNA-mediated depletion of either factor delays short-loop β3 integrin recycling from the early endosome back to the cell surface."
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AAK1L kinase activity and its C-terminal domain are required to maintain cell adhesion.
"Moreover, structure-function analysis reveals that AAK1L kinase activity, as well as its C-terminal domain, is essential for cell adhesion maintenance."
Family-wide Structural Analysis of Human Numb-Associated Protein Kinases.
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The human AAK1 kinase domain was structurally resolved at 1.95 Å in an inhibitor-bound complex.
"The structure of AAK1 was solved in complex with a small-molecule inhibitor to 1.95 Å resolution in space group P212121 with two AAK1 kinase domains per asymmetric unit (chains A and B) (Table 1)."
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Recombinant AAK1 directly phosphorylated an AP2-medium-subunit-derived peptide in vitro.
"A 17-mer synthetic peptide corresponding to the AAK1/BIKE phosphorylation site on the medium subunit of AP2 was used to test kinase activity. Phosphorylation of the substrate in the presence of AAK1 was confirmed by mass spectrometry (Figure S1)."
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AAK1's assembled regulatory spine without activation-loop phosphorylation supports constitutive catalytic competence.
"Similarly, in structures of BIKE and AAK1 there is alignment of the R spine in the absence of phosphorylation, suggesting that NAK family members are constitutively active kinases (Figure 2C)."
WNT Activates the AAK1 Kinase to Promote Clathrin-Mediated Endocytosis of LRP6 and Establish a Negative Feedback Loop.
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Human cell-line perturbations establish AAK1 as a negative regulator of WNT signaling across multiple tissue-derived models.
"Together, these data establish that AAK1 negatively regulates WNT signaling in cells derived from multiple tissue types."
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AAK1 promotes clathrin-mediated endocytosis and lysosomal degradation of LRP6, forming a negative-feedback mechanism for WNT signaling.
"Together, these results suggest that AAK1 inhibits WNT signaling by inducing CME endocytosis and lysosomal degradation of LRP6."
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Delayed WNT3A-induced phosphorylation of AP2M1 requires AAK1 expression and kinase activity.
"The WNT3A-induced phosphorylation of AP2M1 required AAK1 expression and activity."
Dysregulation of the AP2M1 phosphorylation cycle by LRRK2 impairs endocytosis and leads to dopaminergic neurodegeneration.
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With equimolar recombinant kinases, AAK1 phosphorylated AP2M1 more potently than LRRK2 in vitro.
"Our results showed that AAK1 was more potent than LRRK2 in phosphorylating AP2M1 in vitro."
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In human SH-SY5Y cells, AAK1 increased endogenous AP2M1 phosphorylation independently of LRRK2.
"We found that AAK1 increased the amount of endogenous AP2M1 phosphorylation in both LRRK2 WT and KO cells (Fig. 3, E and F), suggesting that AAK1 can phosphorylate AP2M1 independently of LRRK2."
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Mouse tissue evidence indicates low relative AAK1 abundance in brain but high abundance in thyroid.
"Notably, we found that unlike LRRK2, the expression of AAK1 was relatively low in mouse brain tissue (Fig. 3, I and J). In contrast, AAK1 was highly expressed in the mouse thyroid gland where LRRK2 expression was relatively low."
AAK1 activation-mediated iron trafficking drives ferroptotic cell death.
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Recombinant active PKCβII directly phosphorylates AAK1; phosphatase treatment removes the signal.
"The level of Ser/Thr phosphorylation of AAK1 protein increased significantly in the presence of recombinant active PKCβII kinase, but was blocked in the addition of λ-phosphatase (Fig. 3E, F)."
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Activated AAK1 phosphorylates AP2M1, promoting clathrin-dependent TFR1 endocytosis, cellular iron accumulation, and ferroptosis.
"Mechanistically, activated AAK1 phosphorylates AP2M1, which facilitates the recruitment of clathrin to mediate the endocytosis of TFR1, increasing the levels of both cellular total iron and ferrous iron and thereby promoting ferroptosis."
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In nude-mouse xenografts of human MDA-MB-231 cells, AAK1 loss reduced IKE-induced ferroptosis and increased tumor growth.
"To further confirm the role of AAK1 during the process of ferroptosis in vivo, we performed xenograft tumor model by inoculating AAK1-knockout MDA-MB-231 cells with or without transfecting plasmids of wild-type or S670/T674Ala mutant AAK1 into nude mice. These nude mice were treated with IKE (a lipid-soluble form of erastin for animal experiment) or DMSO as control. As expected, knockout of AAK1 significantly inhibited ferroptosis through resistance of lipid peroxidation induced by IKE and promoted tumor growth (Fig. 6G–J)."
AAK1-mediated phosphorylation of PDLIM5 and Talin1 promotes focal adhesion disassembly to accelerate cell migration.
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Biochemical and phosphoproteomic screens identify PDLIM5 and Talin1 as direct AAK1/BMP2K substrates.
"Here, using motif-guided in silico, biochemical, and phosphoproteomic screens, we identify PDLIM5 and Talin1 as direct AAK1/BMP2K substrates."
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AAK1 has a specific, nonredundant kinase-dependent role in focal-adhesion turnover and cell migration in human RPE cells.
"AAK1 deletion or siRNA-mediated knockdown reproducibly impaired RPE migration by ~25% (Fig. 3d, e and Supplementary Fig. 1h), whereas BMP2K loss had no measurable effect, revealing a specific and non-redundant role for AAK1 in cell motility."
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Human RPE-cell phosphoproteomics and in-vitro kinase assays failed to support NUMB Thr102 as an AAK1/BMP2K substrate, directly disputing the PMID:18657069 claim.
"Furthermore, our global phosphoproteome profiling of RPE cells failed to detect phosphorylation of the previously proposed substrates Dab2 T109, Arh T104, or NUMB T102. This conclusion is supported by both our in vitro kinase assays and the absence of phosphorylation evidence in high-throughput databases, such as PhosphoSitePlus (Fig. 1h, i), which suggests that Dab2 T109, Arh T104, and NUMB T102 are unlikely to be physiological targets of AAK1 or BMP2K."
Recruitment of AP-2 complex and clathrin
AAK1 phosphorylates AP-2 mu subunit at T156
ARBB recruits GPCRs into clathrin-coated pits
F- and N- BAR domain proteins bind the clathrin-coated pit
CLASP proteins and cargo are recruited to the nascent clathrin-coated pit
Clathrin recruits PIK3C2A
Clathrin-associated PIK3C2A phosphorylates PI(4)P to PI(3,4)P2
SNX9 recruits components of the actin polymerizing machinery
BAR domain proteins recruit dynamin
SYNJ hydrolyze PI(4,5)P2 to PI(4)P
Endophilins recruit synaptojanins to the clathrin-coated pit
HSPA8-mediated ATP hydrolysis promotes vesicle uncoating
Clathrin recruits auxilins to the clathrin-coated vesicle
Auxilin recruits HSPA8:ATP to the clathrin-coated vesicle
Dynamin-mediated GTP hydrolysis promotes vesicle scission
Dissociation of AAK1 and dephosphorylation of AP-2 mu2
RAB5 and GAPVD1 bind AP-2