Rare Diseases Symptoms Automatic Extraction
Home
A random Abstract
Our Project
Our Team
The calcium-activated neutral protease calpain I is present in normal foetal skin and is decreased in neonatal harlequin ichthyosis.
[harlequin ichthyosis]
Calcium
concentration
is
a
critical
factor
for
epidermal
differentiation
and
is
implicated
in
the
expression
and
post-translational
modification
of
numerous
proteins
in
suprabasal
cells
of
the
epidermis
.
Calpains
(
calcium
-activated
neutral
proteases
)
are
believed
to
participate
in
signal
transduction
via
highly
regulated
cytoplasmic
protease
activity
.
Here
we
investigate
the
expression
of
calpain
I
in
normal
human
skin
development
and
in
neonatal
harlequin
ichthyosis
(
HI
)
,
a
disorder
of
altered
epidermal
differentiation
,
especially
the
transition
from
the
granular
to
the
fully
differentiated
cornified
layer
.
Calpain
I
was
detected
in
developing
foetal
epidermis
at
54
days
estimated
gestational
age
in
the
basal
layer
and
the
periderm
of
the
developing
foetal
epidermis
.
By
125
days
,
calpain
I
was
also
detected
in
the
granular
layer
.
This
pattern
was
maintained
in
newborn
skin
,
but
expression
was
significantly
weaker
in
HI
biopsies
(
n
=
7
)
.
Reduced
expression
of
calpain
was
specific
to
HI
and
was
not
observed
in
other
skin
diseases
.
Calpain
was
also
normally
expressed
in
the
outer
root
sheath
of
hair
follicles
,
in
sebaceous
glands
and
in
sweat
ducts
and
glands
.
Immunoblots
of
epidermal
and
keratinocyte
extracts
showed
that
the
78
-
kDa
and
76
-
kDa
active
forms
were
generated
via
limited
proteolysis
of
the
80
-
kDa
inactive
subunit
;
however
,
all
forms
were
diminished
in
HI
,
consistent
with
findings
in
tissue
sections
.
Our
results
show
that
calpain
is
present
throughout
the
epidermis
and
is
expressed
from
the
early
stages
of
development
.
These
findings
implicate
calcium
-mediated
signalling
events
in
the
alteration
of
differentiation
that
occurs
in
HI
.