RRC ID 53390
Author Norris A, Tammineni P, Wang S, Gerdes J, Murr A, Kwan KY, Cai Q, Grant BD.
Title SNX-1 and RME-8 oppose the assembly of HGRS-1/ESCRT-0 degradative microdomains on endosomes.
Journal Proc Natl Acad Sci U S A
Abstract After endocytosis, transmembrane cargo reaches endosomes, where it encounters complexes dedicated to opposing functions: recycling and degradation. Microdomains containing endosomal sorting complexes required for transport (ESCRT)-0 component Hrs [hepatocyte growth factor-regulated tyrosine kinase substrate (HGRS-1) in Caenorhabditis elegans] mediate cargo degradation, concentrating ubiquitinated cargo and organizing the activities of ESCRT. At the same time, retromer associated sorting nexin one (SNX-1) and its binding partner, J-domain protein RME-8, sort cargo away from degradation, promoting cargo recycling to the Golgi. Thus, we hypothesized that there could be important regulatory interactions between retromer and ESCRT that balance degradative and recycling functions. Taking advantage of the naturally large endosomes of the C. elegans coelomocyte, we visualized complementary ESCRT-0 and RME-8/SNX-1 microdomains in vivo and assayed the ability of retromer and ESCRT microdomains to regulate one another. We found in snx-1(0) and rme-8(ts) mutants increased endosomal coverage and intensity of HGRS-1-labeled microdomains, as well as increased total levels of HGRS-1 bound to membranes. These effects are specific to SNX-1 and RME-8, as loss of other retromer components SNX-3 and vacuolar protein sorting-associated protein 35 (VPS-35) did not affect HGRS-1 microdomains. Additionally, knockdown of hgrs-1 had little to no effect on SNX-1 and RME-8 microdomains, suggesting directionality to the interaction. Separation of the functionally distinct ESCRT-0 and SNX-1/RME-8 microdomains was also compromised in the absence of RME-8 and SNX-1, a phenomenon we observed to be conserved, as depletion of Snx1 and Snx2 in HeLa cells also led to greater overlap of Rme-8 and Hrs on endosomes.
Volume 114(3)
Pages E307-E316
Published 2017-1-17
DOI 10.1073/pnas.1612730114
PII 1612730114
PMID 28053230
PMC PMC5255583
MeSH Animals Animals, Genetically Modified Caenorhabditis elegans / genetics Caenorhabditis elegans / metabolism Caenorhabditis elegans Proteins / antagonists & inhibitors Caenorhabditis elegans Proteins / genetics Caenorhabditis elegans Proteins / metabolism* Endosomal Sorting Complexes Required for Transport / antagonists & inhibitors Endosomal Sorting Complexes Required for Transport / genetics Endosomal Sorting Complexes Required for Transport / metabolism* Endosomes / metabolism* Gene Knockdown Techniques HeLa Cells Humans Molecular Chaperones Phosphoproteins / antagonists & inhibitors Phosphoproteins / genetics Phosphoproteins / metabolism* Protein Interaction Domains and Motifs Protein Transport Proteolysis RNA, Small Interfering / genetics Recombinant Proteins / genetics Recombinant Proteins / metabolism Sorting Nexins / antagonists & inhibitors Sorting Nexins / genetics Sorting Nexins / metabolism*
IF 9.412
Times Cited 26
C.elegans tm847 tm1595 tm3790