SFT-4/Surf4 control ER export of soluble cargo proteins and participate in ER exit site organization

Saegusa, Keiko; Sato, Miyuki; Morooka, Nobukatsu; Hara, Taichi; Sato, Ken

doi:10.1083/jcb.201708115

Cited by 65 publications

(81 citation statements)

References 39 publications

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“…FLAG-tagged SURF4 demonstrated similar rescue of PCSK9-eGFP fluorescence in SURF4deficient cells compared to native, untagged SURF4 ( Figure 3E), demonstrating that this tag does not interfere with SURF4 function. Consistent with previous reports 20, 21 and compatible with a role for SURF4 as an ER cargo receptor, immunofluorescence of FLAG-SURF4 demonstrated colocalization with a marker of the ER and, to a lesser extent, the ERGIC compartment ( Figure 4A-B). Co-immunoprecipitation of cell lysates prepared in the presence of the chemical crosslinker dithiobis(succinimidyl propionate) demonstrated a physical interaction between FLAG-tagged SURF4 and GFP-tagged PCSK9 ( Figure 4D).…”

Section: Surf4 Deletion Causes Intracellular Accumulation Of Pcsk9-egsupporting

confidence: 92%

“…Though a loss-of-function variant (p.Gln185Ter) is present in ~1:500 individuals 38 , no human diseases have been associated with SURF4 deficiency and no mouse models for Surf4 deletion have been reported 39 . Erv29, the SURF4 homolog in yeast, is required for gpαf secretion and the C. elegans homolog (SFT-4) facilitates the secretion of yolk lipoproteins 21 , with the latter report also demonstrating a role for SURF4 in apolipoprotein B secretion in HepG2 cells. Thus, it seems highly likely that additional SURF4 cargoes remain to be identified.…”

Section: Discussionmentioning

confidence: 91%

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The cargo receptor SURF4 promotes the efficient cellular secretion of PCSK9

Emmer

Hesketh

Kotnik

et al. 2018

Preprint

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Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a secreted protein that plays an important role in regulating plasma cholesterol and cardiovascular disease risk. PCSK9 secretion uniquely depends on the cytoplasmic COPII protein SEC24A, suggesting the presence of a transmembrane ER cargo receptor mediating this interaction. Here, we report a novel approach that combines proximity-dependent biotinylation and proteomics together with genome-scale CRISPR screening to identify proteins that facilitate the efficient secretion of PCSK9 heterologously expressed in HEK293T cells. We first identified 35 candidate proteins that were labeled by BirA* fusions to PCSK9 and either COPII component SAR1A or SAR1B.We then performed genome-scale pooled CRISPR mutagenesis to identify genes whose perturbation resulted in intracellular accumulation of PCSK9-eGFP but not the control A1AT-mCherry. The 4 most enriched sgRNAs in this screen all targeted SURF4, a homologue of the yeast endoplasmic reticulum (ER) cargo receptor Erv29p and the only candidate also identified by proximity-dependent biotinylation. The functional contribution of SURF4 to PCSK9 secretion was confirmed with multiple independent SURF4-targeting sgRNAs, clonal SURF4-deficient cell lines, and functional rescue with SURF4 cDNA. Compatible with a function of SURF4 as a cargo receptor for PCSK9, fluorescence microscopy localized SURF4 to the early secretory pathway, coimmunoprecipitation revealed a physical interaction between SURF4 and PCSK9, and SURF4 deletion resulted in decreased extracellular secretion of PCSK9 and PCSK9 accumulation in the ER. Taken together, these findings support a model in which SURF4 functions as an ER cargo receptor for the efficient cellular secretion of PCSK9.All rights reserved. No reuse allowed without permission.

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Section: Surf4 Deletion Causes Intracellular Accumulation Of Pcsk9-egsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 91%

The cargo receptor SURF4 promotes the efficient cellular secretion of PCSK9

Emmer

Hesketh

Kotnik

et al. 2018

Preprint

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“…These experiments relied on heterologous expression of PCSK9 in HEK293T cells, however, and the physiologic relevance of this interaction in vivo remains uncertain. Additionally, although SURF4 deletion did not affect the secretion of a control protein, alpha-1 antitrypsin, a broader role for SURF4 in protein secretion remains possible and is supported by the recent identification of other potential cargoes including apolipoprotein B, growth hormone, DSPP, and amelogenin 4,5 .…”

Section: Introductionmentioning

confidence: 98%

Murine Surf4 is essential for early embryonic development

Emmer

Lascuna

Kotnik

et al. 2019

Preprint

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Newly synthesized proteins co-translationally inserted into the endoplasmic reticulum (ER) lumen may be recruited into anterograde transport vesicles by their association with specific cargo receptors. We recently identified a role for the cargo receptor SURF4 in facilitating the secretion of PCSK9 in cultured cells. To examine the function of SURF4 in vivo, we used CRISPR/Cas9-mediated gene editing to generate mice with germline loss-of-function mutations in Surf4. Surf4 +/mice exhibited grossly normal appearance, behavior, body weight, fecundity, and organ development and demonstrated no significant alterations in circulating plasma levels of PCSK9, apolipoprotein B, or total cholesterol. Surf4 -/mice exhibit embryonic lethality, with complete loss of all Surf4 -/offspring between embryonic days 3.5 and 9.5. Taken together with the much milder phenotypes of PCSK9 or apolipoprotein B deficiency in mice, these findings imply the existence of additional SURF4 cargoes or functions that are essential for murine early embryonic development.

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“…There is a precedent for CopI-dependent return of cargo receptors to the ER. Yeast Erv29p and its C. elegans homolog, SFT-4/Surf4 (Surfeit locus protein 4 homolog), are ER-localized membrane proteins required for the efficient CopIImediated export of specific soluble cargo proteins; these cargo receptors are returned to the ER in CopI coated vesicles (69). TANGO1 (Transport and Golgi organization protein 1), a Type 1 ER-localized membrane protein, delivers procollagen to departing COPII vesicles, but remains in the ER (67).…”

Section: Discussionmentioning

confidence: 99%

A Single Membrane Protein Required for Atrial Secretory Granule Formation

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Luxmi

Powers

et al. 2020

Preprint

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Conflicts:The authors declare no conflict of interest.Classification: Biological Sciences (major); Cell Biology (minor) Abstract:The discovery of atrial secretory granules and the natriuretic peptides stored in them identified the atrium as an endocrine organ. Although neither atrial nor brain natriuretic peptide (ANP, BNP) is amidated, the major membrane protein in atrial granules is Peptidylglycine -Amidating Monooxygenase (PAM), an enzyme essential for amidated peptide biosynthesis. Mice lacking cardiomyocyte PAM (Pam Myh6-cKO/cKO ) are viable, but a gene dosage-dependent drop in atrial ANP and BNP content occurred. Ultrastructural analysis of adult Pam Myh6-cKO/cKO atria revealed a 20-fold drop in the volume fraction of secretory granules and a decrease in peripherally localized Golgi complexes. When primary cultures of Pam 0-Cre-cKO/cKO atrial myocytes (PAM floxed, no Cre recombinase) were transduced with Cre-GFP lentivirus, PAM protein levels dropped, followed by a decline in proANP levels. Expression of exogenous PAM in Pam Myh6-cKO/cKO atrial myocytes produced a dose-dependent increase in proANP content. Strikingly, rescue of proANP content did not require the monooxygenase activity of PAM. Unlike many prohormones, atrial proANP is stored intact and its basal secretion is stimulated by drugs that inhibit Golgi-localized Arf activators. Increased basal secretion of proANP was a major contributor to its reduced levels in Pam Myh6-cKO/cKO myocytes; the inability of these drugs to inhibit basal proANP secretion by Pam Myh6-cKO/cKO myocytes revealed a role for COPI-mediated recycling of PAM to the endoplasmic reticulum. Analysis of atrial coated vesicles and the ability PAM to make fluorescently-tagged proANP accumulate in the cis-Golgi region of cells lacking secretory granules revealed a non-catalytic role for PAM in soluble cargo trafficking early in the secretory pathway. Significance:Transmission electron microscopy of atrial cardiomyocytes revealed dense granules resembling those in endocrine cells and neurons, leading to the discovery of the natriuretic peptides stored in these granules. Subsequent studies revealed features unique to atrial granules, including high level expression of Peptidylglycine -Amidating Monooxygenase (PAM), an enzyme required for the synthesis of many neuropeptides, but not for the synthesis of natriuretic peptides. The discovery that atrial myocytes lacking PAM are unable to produce granules and that PAM lacking its monooxygenase activity can rescue granule formation provides new information about the proANP secretory pathway. A better understanding of the unique features of atrial cell biology should provide insight into atrial fibrillation, the most common cardiac arrhythmia, atrial amyloidosis and heart failure. RESULTS Secretory granules are rarely seen in the atria of Pam Myh6-cKO/cKO miceWe turned to transmission electron microscopy to determine whether the drop in proANP levels observed in the atria of Pam Myh6-cKO/cKO mice (3) were accompanied by a decrease in the num...

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SFT-4/Surf4 control ER export of soluble cargo proteins and participate in ER exit site organization

Cited by 65 publications

References 39 publications

The cargo receptor SURF4 promotes the efficient cellular secretion of PCSK9

The cargo receptor SURF4 promotes the efficient cellular secretion of PCSK9

Murine Surf4 is essential for early embryonic development

A Single Membrane Protein Required for Atrial Secretory Granule Formation

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