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GRP75 upregulates clathrin-independent endocytosis through actin cytoskeleton reorganization mediated by the concurrent activation of Cdc42 and RhoA

Chen, Hang; Gao, Zhihui; He, Changzheng; Xiang, Rong; van Kuppevelt, Toin H.; Belting, Mattias LU and Zhang, Sihe LU (2016) In Experimental Cell Research 343(2). p.223-236
Abstract

Therapeutic macromolecules are internalized into the cell by either clathrin-mediated endocytosis (CME) or clathrin-independent endocytosis (CIE). Although some chaperone proteins play an essential role in CME (e.g. Hsc70 in clathrin uncoating), relatively few of these proteins are functionally involved in CIE. We previously revealed a role for the mitochondrial chaperone protein GRP75 in heparan sulfate proteoglycan (HSPG)-mediated, membrane raft-associated macromolecule endocytosis. However, the mechanism underlying this process remains unclear. In this study, using a mitochondrial signal peptide-directed protein trafficking expression strategy, we demonstrate that wild-type GRP75 expression enhanced the uptakes of HSPG and CIE marker... (More)

Therapeutic macromolecules are internalized into the cell by either clathrin-mediated endocytosis (CME) or clathrin-independent endocytosis (CIE). Although some chaperone proteins play an essential role in CME (e.g. Hsc70 in clathrin uncoating), relatively few of these proteins are functionally involved in CIE. We previously revealed a role for the mitochondrial chaperone protein GRP75 in heparan sulfate proteoglycan (HSPG)-mediated, membrane raft-associated macromolecule endocytosis. However, the mechanism underlying this process remains unclear. In this study, using a mitochondrial signal peptide-directed protein trafficking expression strategy, we demonstrate that wild-type GRP75 expression enhanced the uptakes of HSPG and CIE marker cholera toxin B subunit but impaired the uptake of CME marker transferrin. The endocytosis regulation function of GRP75 is largely mediated by its subcellular location in mitochondria and is essentially determined by its ATPase domain. Interestingly, the mitochondrial expression of GRP75 or its ATPase domain significantly stimulates increases in both RhoA and Cdc42 activation, remarkably induces stress fibers and enhances filopodia formation, which collectively results in the promotion of CIE, but the inhibition of CME. Furthermore, silencing of Cdc42 or RhoA impaired the ability of GRP75 overexpression to increase CIE. Therefore, these results suggest that endocytosis vesicle enrichment of GRP75 by mitochondria trafficking upregulates CIE through an actin cytoskeleton reorganization mechanism mediated by the concurrent activation of Cdc42 and RhoA. This finding provides novel insight into organelle-derived chaperone signaling and the regulation of different endocytosis pathways in cells.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Actin cytoskeleton, ATPase domain, Cdc42, Clathrin-independent endocytosis, GRP75, RhoA
in
Experimental Cell Research
volume
343
issue
2
pages
14 pages
publisher
Academic Press
external identifiers
  • Scopus:84963960246
ISSN
0014-4827
DOI
10.1016/j.yexcr.2016.04.009
language
English
LU publication?
yes
id
bcee2c3b-1b54-4837-96f0-2b7123f08aa7
date added to LUP
2016-09-22 11:28:49
date last changed
2016-09-23 03:00:01
@misc{bcee2c3b-1b54-4837-96f0-2b7123f08aa7,
  abstract     = {<p>Therapeutic macromolecules are internalized into the cell by either clathrin-mediated endocytosis (CME) or clathrin-independent endocytosis (CIE). Although some chaperone proteins play an essential role in CME (e.g. Hsc70 in clathrin uncoating), relatively few of these proteins are functionally involved in CIE. We previously revealed a role for the mitochondrial chaperone protein GRP75 in heparan sulfate proteoglycan (HSPG)-mediated, membrane raft-associated macromolecule endocytosis. However, the mechanism underlying this process remains unclear. In this study, using a mitochondrial signal peptide-directed protein trafficking expression strategy, we demonstrate that wild-type GRP75 expression enhanced the uptakes of HSPG and CIE marker cholera toxin B subunit but impaired the uptake of CME marker transferrin. The endocytosis regulation function of GRP75 is largely mediated by its subcellular location in mitochondria and is essentially determined by its ATPase domain. Interestingly, the mitochondrial expression of GRP75 or its ATPase domain significantly stimulates increases in both RhoA and Cdc42 activation, remarkably induces stress fibers and enhances filopodia formation, which collectively results in the promotion of CIE, but the inhibition of CME. Furthermore, silencing of Cdc42 or RhoA impaired the ability of GRP75 overexpression to increase CIE. Therefore, these results suggest that endocytosis vesicle enrichment of GRP75 by mitochondria trafficking upregulates CIE through an actin cytoskeleton reorganization mechanism mediated by the concurrent activation of Cdc42 and RhoA. This finding provides novel insight into organelle-derived chaperone signaling and the regulation of different endocytosis pathways in cells.</p>},
  author       = {Chen, Hang and Gao, Zhihui and He, Changzheng and Xiang, Rong and van Kuppevelt, Toin H. and Belting, Mattias and Zhang, Sihe},
  issn         = {0014-4827},
  keyword      = {Actin cytoskeleton,ATPase domain,Cdc42,Clathrin-independent endocytosis,GRP75,RhoA},
  language     = {eng},
  month        = {05},
  number       = {2},
  pages        = {223--236},
  publisher    = {ARRAY(0x9a75888)},
  series       = {Experimental Cell Research},
  title        = {GRP75 upregulates clathrin-independent endocytosis through actin cytoskeleton reorganization mediated by the concurrent activation of Cdc42 and RhoA},
  url          = {http://dx.doi.org/10.1016/j.yexcr.2016.04.009},
  volume       = {343},
  year         = {2016},
}