Taking sides: Factors that influence patterns in protein distribution


Date:
October 8, 2020
Source:
John Innes Centre
Summary:
A new article has found that even cells in isolation can become
polarized to create the head to tail pattern, and that this polarity
can orient how the cell grows.



FULL STORY ==========================================================================
In plants, many proteins are found at only one end of a cell, giving
them a polarity like heads and tails on a coin.


========================================================================== Often, cells next to each other have these proteins at the same end, like
a stack of coins with heads all facing up. This protein patterning is
critical for how plant cells orient and coordinate themselves to produce
the leaves, flowers, stems and roots that adorn our gardens and provide
us with all our food and the oxygen we breathe.

Previously it's been unclear how this head-to-tail protein patterning is produced: can it arise within each cell, or does it depend on a collective effort of many cells working together? A new paper, published in Current Biology has found that even cells in isolation can become polarised to
create the head to tail pattern, and that this polarity can orient how
the cell grows.

The team, from the John Innes Centre, studied a protein called BASL
that is normally found at only one end of the cells giving rise to leaf
pores. By tagging the BASL protein with fluorescence and introducing it
into cultured plant cells they could see where the protein went.

They showed that even if the cells were stripped of their walls, to
create membrane-enclosed spheres, the BASL protein went to only one end
of the cell, forming a cap. Time-lapse movies showed that position of
BASL labelling changed over time, like a polar ice cap wandering over
the earth's surface. However, when cells reformed their walls, the BASL
cap could become fixed, and cells elongated into sausage shapes, with
the cap remaining at one of the rounded ends.

Lead author Dr Jordi Chan says, "It was incredibly exciting to see
polarity in isolated plant cells for the first time. It was like
seeing a boring-looking planet suddenly light up to reveal a cap,
and then elongating while keeping the cap at one end." The results
show that cell polarity can arise within cells and likely orients their
growth. Signalling between cells may then coordinate polarity, aligning
the heads and tails of different cells in a tissue, guiding how they
grow collectively and develop into a plant.


========================================================================== Story Source: Materials provided by John_Innes_Centre. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Jordi Chan, Catherine Mansfield, Flavie Clouet, Delfi Dorussen,
Enrico
Coen. Intrinsic Cell Polarity Coupled to Growth Axis
Formation in Tobacco BY-2 Cells. Current Biology, 2020; DOI:
10.1016/j.cub.2020.09.036 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201008121304.htm

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