Current Biology
Volume 32, Issue 10, 23 May 2022, Pages 2300-2308.e4
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Report
Determining protein polarization proteome-wide using physical dissection of individual Stentor coeruleus cells

https://doi.org/10.1016/j.cub.2022.03.078Get rights and content
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Highlights

  • Spatial proteomics can be accomplished by physically dissecting cells

  • A quarter of the proteome of a Stentor cell is polarized along the A/P axis

  • PP2a is enriched in the MB and involved in MB morphogenesis

Summary

Cellular components are non-randomly arranged with respect to the shape and polarity of the whole cell.1, 2, 3, 4 Patterning within cells can extend down to the level of individual proteins and mRNA.5,6 But how much of the proteome is actually localized with respect to cell polarity axes? Proteomics combined with cellular fractionation7, 8, 9, 10, 11 has shown that most proteins localize to one or more organelles but does not tell us how many proteins have a polarized localization with respect to the large-scale polarity axes of the intact cell. Genome-wide localization studies in yeast12, 13, 14, 15 found that only a few percent of proteins have a localized position relative to the cell polarity axis defined by sites of polarized cell growth. Here, we describe an approach for analyzing protein distribution within a cell with a visibly obvious global patterning—the giant ciliate Stentor coeruleus.16,17 Ciliates, including Stentor, have highly polarized cell shapes with visible surface patterning.1,18 A Stentor cell is roughly 2 mm long, allowing a “proteomic dissection” in which microsurgery is used to separate cellular fragments along the anterior-posterior axis, followed by comparative proteomic analysis. In our analysis, 25% of the proteome, including signaling proteins, centrin/SFI proteins, and GAS2 orthologs, shows a polarized location along the cell’s anterior-posterior axis. We conclude that a large proportion of all proteins are polarized with respect to global cell polarity axes and that proteomic dissection provides a simple and effective approach for spatial proteomics.

Keywords

subcellular proteomics
cell polarity
cell morphology
patterning
regeneration

Data and code availability

  • All data in this paper will be shared by the lead contact upon request.

  • Original R code to calculate proteomic dissection profiles is provided in the supplementary information

  • Any additional information required to re-analyze the data reported in this paper is available from the lead contact upon request

Cited by (0)

4

Twitter: @WallaceUCSF

5

Lead contact