PMID:25789876

Citation	Huang, LH, Lee, WC, You, ST, Cheng, CC and Yu, CJ (2015) Arfaptin-1 negatively regulates Arl1-mediated retrograde transport. PLoS ONE 10:e0118743
Abstract	The small GTPase Arf-like protein 1 (Arl1) is well known for its role in intracellular vesicular transport at the trans-Golgi network (TGN). In this study, we used differential affinity chromatography combined with mass spectrometry to identify Arf-interacting protein 1b (arfaptin-1b) as an Arl1-interacting protein and characterized a novel function for arfaptin-1 (including the arfaptin-1a and 1b isoforms) in Arl1-mediated retrograde transport. Using a Shiga-toxin subunit B (STxB) transportation assay, we demonstrated that knockdown of arfaptin-1 accelerated the retrograde transport of STxB from the endosome to the Golgi apparatus, whereas Arl1 knockdown inhibited STxB transport compared with control cells. Arfaptin-1 overexpression, but not an Arl1 binding-defective mutant (arfaptin-1b-F317A), consistently inhibited STxB transport. Exogenous arfaptin-1 expression did not interfere with the localization of the Arl1-interacting proteins golgin-97 and golgin-245 to the TGN and vice versa. Moreover, we found that the N-terminal region of arfaptin-1 was involved in the regulation of retrograde transport. Our results show that arfaptin-1 acts as a negative regulator in Arl1-mediated retrograde transport and suggest that different functional complexes containing Arl1 form in distinct microdomains and are responsible for different functions.
Links	PubMed PMC4366199 Online version:10.1371/journal.pone.0118743
Keywords	ADP-Ribosylation Factors/metabolism; Adaptor Proteins, Signal Transducing/genetics; Adaptor Proteins, Signal Transducing/metabolism; Analysis of Variance; Autoantigens/metabolism; Chromatography, Affinity; Fluorescent Antibody Technique; Gene Knockdown Techniques; HeLa Cells; Humans; Mass Spectrometry; Membrane Proteins/metabolism; RNA Interference; Shiga Toxin 2; Vesicular Transport Proteins/metabolism; trans-Golgi Network/metabolism
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
HUMAN:ARFP1		GO:1905280: negative regulation of retrograde transport, endosome to Golgi	ECO:0000315:		P		Organism: Homo sapiens Protein: Arfaptin-1//Arfaptin-1 Figure 2 shows the effects of overexpression of Arfaptin-1 on STxB retrograde transport from the endosome to the Golgi	complete CACAO 12552

References

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