ARL5B, an ARF-like small GTPase localized to the trans-Golgi, is known for regulating endosome-Golgi trafficking and promoting the migration and invasion of breast cancer cells. Although a few interacting partners have been identified, the mechanism of the shuttling of ARL5B between the Golgi membrane and the cytosol is still obscure. Here, using GFP-binding protein (GBP) pull-down followed by mass spectrometry, we identified heat shock cognate protein (HSC70) as an additional interacting partner of ARL5B. Our pull-down and isothermal titration calorimetry (ITC)-based studies suggested that HSC70 binds to ARL5B in an ADP-dependent manner. Additionally, we showed that the N-terminal helix and the nucleotide status of ARL5B contribute to its recognition by HSC70. The confocal microscopy and cell fractionation studies in MDA-MB-231 breast cancer cells revealed that the depletion of HSC70 reduces the localization of ARL5B to the Golgi. Using in vitro reconstitution approach, we provide evidence that HSC70 fine-tunes the association of ARL5B with Golgi membrane. Finally, we demonstrated that the interaction between ARL5B and HSC70 is important for the localization of cation independent mannose-6-phosphate receptor (CIMPR) at Golgi. Collectively, we propose a mechanism by which HSC70, a constitutively expressed chaperone, modulates the Golgi association of ARL5B, which in turn has implications for the Golgi-associated functions of this GTPase.
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http://dx.doi.org/10.1016/j.jbc.2021.101422 | DOI Listing |
Ann Hematol
November 2024
Department of Haematology, The Seventh Affiliated Hospital, Sun Yat-Sen University, Shenzhen, 518000, China.
Acute myeloid leukaemia (AML) was originally an aggressive malignancy of the bone marrow and one of the deadliest forms of acute leukaemia. The 5-year mortality benefit for patients with AML was only 28.3%.
View Article and Find Full Text PDFEMBO J
September 2022
Department of Pharmacology and Moores Cancer Center, University of California San Diego, La Jolla, CA, USA.
FEBS Lett
September 2022
The Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Vic, Australia.
The small G protein Arl5b is localised on the trans-Golgi network (TGN) and regulates endosomes-to-TGN transport. Here, we combined in vivo and in vitro techniques to map the interactive partners and near neighbours of Arl5b at the TGN, using constitutively active, membrane-bound Arl5b(Q70L)-GFP in stably expressing HeLa cells, and the proximity labelling techniques BioID and APEX2 in parallel with GFP-Trap pull down. From MS analysis, 22 Golgi proteins were identified; 50% were TGN-localised Rabs, Arfs and Arls.
View Article and Find Full Text PDFJ Biol Chem
December 2021
Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, India. Electronic address:
ARL5B, an ARF-like small GTPase localized to the trans-Golgi, is known for regulating endosome-Golgi trafficking and promoting the migration and invasion of breast cancer cells. Although a few interacting partners have been identified, the mechanism of the shuttling of ARL5B between the Golgi membrane and the cytosol is still obscure. Here, using GFP-binding protein (GBP) pull-down followed by mass spectrometry, we identified heat shock cognate protein (HSC70) as an additional interacting partner of ARL5B.
View Article and Find Full Text PDFJ Biol Chem
February 2019
Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria 3010, Australia. Electronic address:
Amyloid precursor protein (APP) is processed along the amyloidogenic pathway by the β-secretase, BACE1, generating β-amyloid (Aβ), or along the nonamyloidogenic pathway by α-secretase, precluding Aβ production. The plasma membrane is considered the major site for α-secretase-mediated APP cleavage, but other cellular locations have not been rigorously investigated. Here, we report that APP is processed by endogenous α-secretase at the -Golgi network (TGN) of both transfected HeLa cells and mouse primary neurons.
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