The cargo receptor SURF4 promotes the efficient cellular secretion of PCSK9

Emmer, Brian T.; Hesketh, Geoffrey G.; Kotnik, Emilee N.; Tang, Vi T; Lascuna, Paul J.; Xiang, Jie; Gingras, Anne‐Claude; Chen, Xiaowei; Ginsburg, David

doi:10.1101/336016

Cited by 11 publications

(23 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Additional examples from recent studies include a variety of receptor systems and cargo proteins-Vti1a/b for Golgi export of Neuropeptide-Y (44), SURF4 for the secretion of PCSK9 (45), and p24 for ER export of GPI-anchored proteins (46). Bulk flow or lower-affinity binding to other cargo receptors can explain slower cargo transport (47).…”

Section: Discussionmentioning

confidence: 99%

A CLN6-CLN8 complex recruits lysosomal enzymes at the ER for Golgi transfer

Bajaj

Ronza

Zheng³

et al. 2019

Preprint

View full text Add to dashboard Cite

Lysosomal enzymes are synthesized in the endoplasmic reticulum (ER) and transferred to the Golgi complex by interaction with the Batten disease protein CLN8. Here we investigated the relationship of this pathway with CLN6, an ER-associated protein of unknown function that is defective in a different Batten disease subtype. Experiments focused on protein interaction and trafficking identified CLN6 as an obligate component of a CLN6-CLN8 complex (herein referred to as EGRESS: ER-to-Golgi relaying of enzymes of the lysosomal system) which recruits lysosomal enzymes at the ER to promote their Golgi transfer. Simultaneous deficiency of CLN6 and CLN8 did not aggravate mouse pathology compared to the single deficiencies, indicating that the EGRESS complex works as a functional unit. Mutagenesis experiments showed that the second luminal loop of CLN6 is required for the interaction of CLN6 with the enzymes but dispensable for interaction with CLN8, and in vitro and in vivo studies showed that CLN6 deficiency results in inefficient ER export of lysosomal enzymes and diminished levels of the enzymes at the lysosome. These results identify CLN6 and the EGRESS complex as key players in lysosome biogenesis and shed light on the molecular etiology of Batten disease caused by defects in CLN6.

show abstract

Section: Discussionmentioning

confidence: 99%

A CLN6-CLN8 complex recruits lysosomal enzymes at the ER for Golgi transfer

Bajaj

Ronza

Zheng³

et al. 2019

Preprint

View full text Add to dashboard Cite

show abstract

“…Our screen was designed to focus on post-transcriptional regulators of EPO by placing its expression under the control of a CMV promoter. Screening strategies similar to the one employed in this manuscript and in a recently published report (32) might help identify additional ER cargo receptors for other soluble secreted proteins, and shed more light into the extent of the contribution of “cargo capture” to recruitment of cargos into COPII vesicles.…”

Section: Discussionmentioning

confidence: 90%

“…Erv29p recycles back from Golgi-to-ER via recognition of its well-conserved di-lysine sorting signal by the COPI coat (38). In mammalian cells, only a handful of cargos (APOB, PCSK9, DSSP, AMLEX, and GH) have been shown to depend on SURF4 for efficient secretion (32, 33, 39). However, a recent report demonstrated that mice with germline deletion of Surf4 exhibit early embryonic lethality (40) similar to C. elegans (33), suggesting the presence of one or more SURF4-dependent cargos with a critical function during embryogenesis.…”

Section: Discussionmentioning

confidence: 99%

“…Our findings suggest that modulating SURF4 may be effective for the treatment of disorders of erythropoeisis that are driven by aberrant EPO levels (85–90). Though a handful of other cargos depend on SURF4 for their secretion (32, 33, 39), with additional cargos likely remaining to be identified, targeting SURF4 exclusively in the EPO producing cells might alter plasma EPO levels and therefore regulate erythropoiesis without affecting other SURF4-dependent cargos that are expressed in other cells. Alternatively, an inhibitor that specifically disrupts the SURF4-EPO interaction would also be expected to have no effects on other cargos that bind SURF4.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

The ER cargo receptor SURF4 facilitates efficient erythropoietin secretion

Lin

King

Tang³

et al. 2019

Preprint

View full text Add to dashboard Cite

1Erythropoietin (EPO), a glycoprotein produced by specialized peritubular fibroblasts in 2 the kidney, is the master regulator of erythropoiesis. EPO is secreted into the plasma in 3 response to tissue hypoxia and stimulates erythroid differentiation and maturation. 4Though the transcriptional regulation of EPO has been well studied, the molecular 5 determinants of EPO secretion remain unknown. Here, we generated a HEK293T 6 reporter cell line that provides a quantifiable and selectable readout of intracellular EPO 7 levels. Using this cell line, we performed a genome-scale CRISPR screen that identified 8 SURF4 as an important mediator of EPO secretion. Targeting SURF4 with multiple 9 independent sgRNAs resulted in intracellular accumulation and extracellular depletion 10 of EPO. Both of these phenotypes were rescued by expression of SURF4 cDNA. 11Additionally, consistent with a role for SURF4 as an ER cargo receptor of EPO, we found 12 that disruption of SURF4 resulted in accumulation of EPO in the ER compartment, and 13 that SURF4 and EPO physically interact. Furthermore, SURF4 disruption in Hep3B 14 cells also caused a defect in the secretion of endogenous EPO, ruling out an artifact of 15 heterologous overexpression. This work suggests that SURF4 functions as an ER cargo 16 receptor that mediates the efficient secretion of EPO. Our findings also suggest that 17 modulating SURF4 may be an effective treatment for disorders of erythropoeisis that 18 are driven by aberrant EPO levels. Finally, we show that SURF4 overexpression results 19 in increased secretion of EPO, suggesting a new strategy for more efficient production of 20 recombinant EPO. 21

show abstract

“…The mammalian homologs of yeast ER vesicle (Erv) proteins have also been thought to function as cargo receptors (Dancourt and Barlowe, 2010). One of these proteins, SURF4, binds amino-terminal tripeptide motifs of soluble cargo proteins and regulates ER export of soluble cargo proteins including the yolk protein VIT-2 in Caenorhabditis elegans (Saegusa et al, 2018), and PCSK9 and apolipoprotein B in mammalian cells (Emmer et al, 2018;Yin et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Anin vitrovesicle formation assay to analyze protein sorting in the secretory transport pathway

Huang

Yin

Tang

et al. 2020

Preprint

View full text Add to dashboard Cite

The fidelity of protein transport in the secretory transport pathway relies on the accurate sorting of proteins to their correct destination. To deepen our understanding of the underlying molecular mechanisms, it is important to develop a robust approach to systematically reveal cargo proteins that depend on a specific cargo sorting machinery to be efficiently packaged into vesicles. Here, we used an in vitro assay that reconstitutes packaging of human cargo proteins into vesicles to quantify cargo capture. Quantitative mass spectrometry analyses of the isolated vesicles revealed novel cytosolic proteins that are associated with vesicle membranes in a GTP-dependent manner or that interact with GTP-bound Sar1A on vesicle membranes. Functional analysis indicates that two of them, FAM84B and PRRC1, regulate anterograde trafficking. Comparing control cells with cells depleted of the cargo receptors, SURF4 or ERGIC53, we revealed specific clients of each of these two export adaptors.Moreover, our results indicate that vesicles enriched with a specific cargo protein contain specific transmembrane cargo and SNARE proteins. A SNARE protein, Vti1B, is identified to be in vesicles enriched with a planar cell polarity protein, Frizzled6, and promotes vesicular release of Frizzled6. Our results indicate that the vesicle formation assay in combination with quantitative mass spectrometric analysis is a robust and powerful tool to reveal novel cytosolic and transmembrane proteins that regulate trafficking of a specific cargo protein.

show abstract

The cargo receptor SURF4 promotes the efficient cellular secretion of PCSK9

Cited by 11 publications

References 56 publications

A CLN6-CLN8 complex recruits lysosomal enzymes at the ER for Golgi transfer

A CLN6-CLN8 complex recruits lysosomal enzymes at the ER for Golgi transfer

The ER cargo receptor SURF4 facilitates efficient erythropoietin secretion

Anin vitrovesicle formation assay to analyze protein sorting in the secretory transport pathway

Contact Info

Product

Resources

About