Internship Report

Investigation of XRCC4/C-terminus Phosphorylation Role on Xkr4 Activation

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Xk-related protein 4 (Xkr4) protein is one of the scramblases that can expose phosphatidylserine
(PS) as an “eat-me” signal in apoptotic cells. Xkr4 is activated in two steps: Dimer formation after
caspase-mediated cleavage of its cytoplasmic region, followed by direct binding of the C-terminal
fragment of X-Ray Repair Cross Complementing 4 (XRCC4/C-terminus) to the Xkr4 dimer. It has been
widely known that hyper-phosphorylated XRCC4/C-terminus is important for DNA repair, but its effect
on Xkr4 activation has never been examined. This project tries to examine the effect of XRCC4/Cterminus
phosphorylation
on
Xkr4
through
Alanine
Mutation
Screening
followed
by
Lipid
Scrambling

Assay.
The
result
showed
that
the
loss
of
one
or
two
phosphorylation
in
XRCC4/C-terminus
does
not

affects
Xkr4
activity,
thus
indicate
that
phosphorylation
of
the
XRCC4/C-terminus
was
not
sufficient
to

affect
Xkr4
activation.
In
the
future,
the
Lipid
Scrambling
Assay
can
be
repeated.
The
phosphorylation

status
of
the
XRCC4/C-terminus
in
active
Xkr4
also
can
be
observed
using mass spectrometry. Other than that, the Xkr4 activity of PLB cells expressing XRCC4/C-terminus mutant without any
phosphorylation site also can be checked with Lipid Scrambling Assay in a future experiment.

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Availability

Detail Information

Series Title

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Call Number

BM 22-027

Publisher

i3L, Jakarta : i3L, Jakarta., 2022

Collation

-

Language

English

ISBN/ISSN

-

Classification

NONE

Content Type

-

Media Type

-

Carrier Type

-

Edition

-

Subject(s)

XRCC4/C-terminus
Phosphorylation
Xkr4
Phosphatidylserine
Phosphatidylcholine
Scramblase
Alanine Mutation Screening
Lipid Scrambling Assay

Specific Detail Info

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Statement of Responsibility

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Other version/related

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