Vol. 86, No. 3, 1979 February 14, 1979
BIOCHEMICAL
AND BIOPHYSICAL RESEARCH COMMUNICATIONS Pages 862-868
RIBOSOMAL PHOSPHOPROTEINS IN PHYSARUM POLYCEPHALUM Gilles
Bglanger,
Dept.
of Biochemistry,
Received
January
Guy Bellemare
and G6rald
Lemieux
Fat. Sciences, Lava1 University, Canada GiK 7P4
2,
Quebec,
1979
SUMMARY Ribosomd proteins of Physarum polycephalum were labelled --in vivo with 32~04. Three acid phosphoproteins were observed in the large subunit, while two basic ones were present in the small subunit. Ribosomal phosphoprotein S3 accounted for 70% of the total radioactivity and may be equivalent to ~6 from rat liver.
INTRODUCTION The phosphorylation has been level
reported
in many recent
and number
of phosphoproteins
(7))
addition
(2),
or during
this
phenomenonmay
of hormones
Studies
the
cell
ribosomes
aminoacyl-tRNA
initiation
on a natural
and initiation tested
binding,
with
viral
partial
control
--in vitro
have not peptide
hepatectomy suggest
normal
that synthesis.
and
shown any correlations
bona
formation,
However,
the
specific
infection
of protein with
in the
or
termination
mRNA has not yet been
(11). --In vitro
kinases
phosphorylation
has been
labelled
than
as --in vivo
of limited
--in vivo
phosphorylated
and it
proteins
of ribosomes use. will
purified
protein
more proteins
have to be shown proven
were modified
(12).
@ 1979 by Academic Press, Inc. of reproduc:ion in any form reserved.
with
Generally,
0006-291X/79/030862-07$01.00/0 Copyright All rights
(g),
in the
--in vivo
Changes
Many results
template.
a cell
(1-6). after
(10).
synthesis
proteins
occur c-AMP
be involved
treated
ribosomal
studies
(8), cycle
of protein
phosphatase with
of eukaryotic
862
at the
same site
were if
--in vitro
the
Vol. 86, No. 3, 1979
It the
BIOCHEMICAL
seems that
further
establishment
physiological
of cells
The acellular
slime
cultures by mitosis
states
of differentiation
can be studied
plasmodia
an exact
natural
occuring
up to lO* nuclei
synchrony.
(13).
Various germination)
This
as a model
during
the
can be grown
sporulation,
be considered
by
phosphorylation.
containing
in the laboratory
of events
between
polycephalum
(spherulation,
can therefore
be accomplished
correlations
mold Physarum
with
easily
investigation
could
and ribosome
as large
dividing
eukaryote
progress
of more precise state
in axenic
AND BIOPHYSICAL RESEARCH COMMUNICATIONS
the
primitive
system
cell
cycle
for
the
and
differentiation. The ribosomal recently ribosomal proteins subunit
(14).
proteins Results
proteins were
acidic
contained
be related
were
labelled
the two basic
electrophoresis
radioactive
spot
liver
organism
in this
ones.
report
(2).
Physarum
show that
by 32PO4.
Combined
The small proteins
may
that
each
one protein.
polycephalum
to study
phospho-
two-dimensional
us to ascertain only
five
Three
subunit.
One of these
contained
in which
have been analyzed
in the large
enabled
effectively show that
organism
in vivo
and present
and SDS gel
interesting
presented
to ~6 from rat
The results
of this
ribosomal
will
be an
protein
phosphorylation.
MATERIAL AND METHODS Submerged cultures of Physarum 01 ce halum, strain M3C, were grown under continual agitation at 2 F---oC In 500 ml flasks containing 50-200 ml of semi-defined medium (13). Cells were labelled for at least 24 hours by addition of 100 uCi/ml of 32P04 to the media in which the KH2 PO4 had been omitted (15). Ribosomes were purified as previously described (14). Briefly, microplasmodia were collected by a gentle centrifugation for 2 minutes at 300 g, after the cell density reached 4-5s v/v. They were then suspended in 2-2.5 volumes of cold buffer TB (0.2M Sucrose; O.lM KCl; O.lM MgC12; O.O25M EDTA; 0.05M Tris-HCl; pH 7.2) and broken with four strokes in a Potter equipped with a Teflon pestle. The
863
BIOCHEMICAL
Vol. 86, No. 3, 1979
AND BIOPHYSICAL RESEARCH COMMUNICATIONS
homogenate was centrifuged for 10 minutes at 15,000 g in a Sorvall The post mitochondrial supernatant was transferred ss-34 rotor. into a 50.2 Ti rotor (Beckman) and the ribosomes were pelleted for 3 hours at 49,000 rpm. The supernatant was discarded and the pellets resuspended in half the initial volume of buffer TB. This crude ribosome preparation was contaminated with polysaccharide, which was elimated by a centrifugation of 30 minutes at 39,000 rpm. The supernatant, containing most of the ribosomes, was centrifuged for 2 hours at 49,000 rpm. The ribosomal proteins were extracted with acetic acid (16) and precipitated with acetone (17). Residual ribosomal RNA was eliminated by incubation of the proteins with a mixture of pancreatic and T2 ribonucleases (6). Two-dimensional electrophoresis was performed according to Kaltschmidt and Wittmann were localized by autoradiography (18). The phosphoproteins and further analyzed by SDS-electrophoresis (19) on a 12-16% gradient of polyacrylamide gel according to Laemmli (20).
RESULTS AND DISCUSSION The two-dimensional the ribosomal
proteins
shown in Figure spots
could ~1, ~20,
after
the
lA.
was incubated showed that
diffuse
staining
radiography can therefore
were
gel spots
were
electrophoresis
cut
gels
disappeared
that
effectively the
out from the two-dimensional The results
864
used,
is five
namely
S3,
be detected in presence
bands
of the
were labelled
five
gel
and only
of migration.
pattern
obtained
and SDS electrophoresis,
in SDS gels.
these
from the
ribosomal data
also
proteins
the front
the
lB),
gel
to electrophoresis.
gave a similar
to correlate
electrophoresis
prior
be seen near
be concluded
autoradiography
could
a sample
pronase
the bands
could
of the
In order
with
were
(Fig.
that
proteins,
of the
proteins
bands
to confirm
phosphorylated
us to resolve
A photograph
of the k-ibosomal
In order
Results
spots.
radioactive
electrophoresis
effectively
67
enabled
by autoradiography
Five
2).
electrophosesis
When 32 PO4 labelled
~24.
of SDS (Fig.
It
into
be detected
sg,
material
gel
(Results
bands
Autonot
detected
shown).
by
phosphoproteins. by two-dimensional the gel
individual
labelled
and submitted
are summarized
to
in Table
1.
Vol. 86, No. 3, 1979
8lOCHEMlCAL
AND BIOPHYSICAL RESEARCH COMMUNICATIONS
b Two dimensional electrophoresis of total ribosomal proteins 1.2 mg according to Kaltschmidt and Wittmann (18). A: Photograph of the gel after staining. B: Autoradiography of the gel after labelling the proteins in Material and --in vivo with 32~14 as described Methods.
F=+
865
Vol.
86,
No.
BIOCHEMICAL
3, 1979
AND
BIOPHYSICAL
RESEARCH
Figure 2. SDS gel electrophoresis of ribosomal proteins vivo with 32~04, as described in Material and Methods. was carried out in 12-16% acrylsmide gradients according (20) A: Photograph of the gel. B: Autoradiogrsm.
The relative proteins protein (70%)
distribution
was also S3 accounted and that
determined for
itwaslocated
of radioactivity (Table
1).
the major
part
in the
866
small
It
COMMUNICATIONS
labelled in Electrophogsis to Laemmli
among the
five
can be seen that
of the
total
subunit.
radioactivity It
may be
BIOCHEMICAL
Vol. 86, No. 3, 1979
AND BIOPHYSICAL RESEARCH COMMUNICATIONS
TABLE1
Ribosomal
proteins
phosphorylated
Molecular
Protein
weight
% total
3.5
L24
15,500
16.5
s9
32,000
3
Ll7
42,000
5
s3
55,000
70
were
labelled
with
32P0
were prepared
--in
related
to protein
~6 of rat
weight
is definitely
higher
function
in ribosome
proteins
belongedto
(55,000
labelled.
The protein
to the
rate
ribosomal
was much less
than
for
results
are phosphorylated to all
organism
is highly
ribosomal
proteins
synchronythrough pathways useful
of Physarum system
in which
cell
its
molecular
However,
its
for
L24, were
weight
similar
and except
Sg had a molecular ~6.
However,
the
acidic
phosphorylation
S3. ribosomes
from
and further It
is
cycle
polycephalum to study
polycephalum
that
of interest
this
to note
phenomenon that
the phosphorylation
early
should
this
of The natural
in evolution.
and multiple
this
Physarum
confirm
and that
has appeared the
(2) although
(14).
subunit,
eukaryotes. primitive
subunits
The three
protein
in vivo,
ribosomal
purified
vs. 36,000).
protein
show that
and
as described in in parenthesis refer
may be equivalent.
the large
weakly
liver
liver
activity
viva
and anilyzed
Material and Methods. Numbers to numeration of proteins from
general
radioactivity
15,000
proteins
is
viva
L20
Cells
These
in
differentiation
make this
phenomenon
organism
a
further.
ACKNOWLEDGMENT This work was supported (Canada) and FCAC (Province
by grants of Qugbec).
867
from National
Research
Council
Vol.
86,
No.
3, 1979
BIOCHEMICAL
AND
BIOPHYSICAL
RESEARCH
COMMUNICATIONS
REFERENCES l2345678910ll121314151617181920-
Kabat, D. (1970) Biochemistry 2, 4160-4175. Gressner, A.M. and Wool, I.G. (1974) J. Biol. Chem. 249. 6917~6925. Rankine, A.U., Leader, D.P. and Coia, A.A. (1977) Biochem. Biophys. Acta 474, 293-307. Schiffmann, D. and Hors&, I. (1978) Eur. J. Biochem. 82, 91-95. Leader, D.P. and Coia, A.A. (1978) Biochem. Biophys. Acta 519, 213-223. Zinker, S. and Warner, J.R. (1976) J. Biol. Chem. 251, 1799-1807. Kaerlin, M., Horsk, I. (1976) Nature 259, 150-151. Blat, C. and Loeb, J.E. (1971) FEBS Lett I& 124-126. Cawthon, M.L., Bitte, L.F., Krystosed, A. and Kabat, D. (1974) J. Biol. Chem. 2@, 275-278. Rupp, R.G., Humphrey, R.M. and Shaeffer, J.R. (1976) Biochem. Biophys. Acta 2, 81-92. Eil, C. and Wool, I.G. (1973) J. Biol. Chem. 248, 5122-5129. Rubin, C.S. and Rosen, O.M. (1975) Ann. Rev. schem. 46, 831-887. Daniel, J.b. and Baldwin, H.M. (1964) In: uMethods in Cell Physiology'. Academic Press, N.Y. 9-41. Lemieux, G., Bglanger, G., Nicole, L. and Bellemare, G. (1978) Submitted for publication. Bersier, D. and Braun, R. (1974) Biochim. Biophys. Acta &I, 46x-471. Hardy, S.J.S., Kurland, C.G., Voynow, P. and Mora, G. (1969) Biochemistry 8, 2897-2905. Barritault, D., Expert-Bezaqon, A., Guerin, M.F. and Hayes, D. (1976) Eur. J. Biochem. 63, 131-135. Kaltschmidt, E. and Wittmann, H.G. (1970) Anal. Biochem. 36, 401-4 Horak, I. and Schiffmann, 0. (1977) Eur. J. Biochem. 79,?75-380. Laemmli, U.K. (1970) Nature g, 680-682.
868
.2.
BIOCHEMICAL
AND BIOPHYSICAL RESEARCH COMMUNICATIONS Pages 862-868
RIBOSOMAL PHOSPHOPROTEINS IN PHYSARUM POLYCEPHALUM Gilles
Bglanger,
Dept.
of Biochemistry,
Received
January
Guy Bellemare
and G6rald
Lemieux
Fat. Sciences, Lava1 University, Canada GiK 7P4
2,
Quebec,
1979
SUMMARY Ribosomd proteins of Physarum polycephalum were labelled --in vivo with 32~04. Three acid phosphoproteins were observed in the large subunit, while two basic ones were present in the small subunit. Ribosomal phosphoprotein S3 accounted for 70% of the total radioactivity and may be equivalent to ~6 from rat liver.
INTRODUCTION The phosphorylation has been level
reported
in many recent
and number
of phosphoproteins
(7))
addition
(2),
or during
this
phenomenonmay
of hormones
Studies
the
cell
ribosomes
aminoacyl-tRNA
initiation
on a natural
and initiation tested
binding,
with
viral
partial
control
--in vitro
have not peptide
hepatectomy suggest
normal
that synthesis.
and
shown any correlations
bona
formation,
However,
the
specific
infection
of protein with
in the
or
termination
mRNA has not yet been
(11). --In vitro
kinases
phosphorylation
has been
labelled
than
as --in vivo
of limited
--in vivo
phosphorylated
and it
proteins
of ribosomes use. will
purified
protein
more proteins
have to be shown proven
were modified
(12).
@ 1979 by Academic Press, Inc. of reproduc:ion in any form reserved.
with
Generally,
0006-291X/79/030862-07$01.00/0 Copyright All rights
(g),
in the
--in vivo
Changes
Many results
template.
a cell
(1-6). after
(10).
synthesis
proteins
occur c-AMP
be involved
treated
ribosomal
studies
(8), cycle
of protein
phosphatase with
of eukaryotic
862
at the
same site
were if
--in vitro
the
Vol. 86, No. 3, 1979
It the
BIOCHEMICAL
seems that
further
establishment
physiological
of cells
The acellular
slime
cultures by mitosis
states
of differentiation
can be studied
plasmodia
an exact
natural
occuring
up to lO* nuclei
synchrony.
(13).
Various germination)
This
as a model
during
the
can be grown
sporulation,
be considered
by
phosphorylation.
containing
in the laboratory
of events
between
polycephalum
(spherulation,
can therefore
be accomplished
correlations
mold Physarum
with
easily
investigation
could
and ribosome
as large
dividing
eukaryote
progress
of more precise state
in axenic
AND BIOPHYSICAL RESEARCH COMMUNICATIONS
the
primitive
system
cell
cycle
for
the
and
differentiation. The ribosomal recently ribosomal proteins subunit
(14).
proteins Results
proteins were
acidic
contained
be related
were
labelled
the two basic
electrophoresis
radioactive
spot
liver
organism
in this
ones.
report
(2).
Physarum
show that
by 32PO4.
Combined
The small proteins
may
that
each
one protein.
polycephalum
to study
phospho-
two-dimensional
us to ascertain only
five
Three
subunit.
One of these
contained
in which
have been analyzed
in the large
enabled
effectively show that
organism
in vivo
and present
and SDS gel
interesting
presented
to ~6 from rat
The results
of this
ribosomal
will
be an
protein
phosphorylation.
MATERIAL AND METHODS Submerged cultures of Physarum 01 ce halum, strain M3C, were grown under continual agitation at 2 F---oC In 500 ml flasks containing 50-200 ml of semi-defined medium (13). Cells were labelled for at least 24 hours by addition of 100 uCi/ml of 32P04 to the media in which the KH2 PO4 had been omitted (15). Ribosomes were purified as previously described (14). Briefly, microplasmodia were collected by a gentle centrifugation for 2 minutes at 300 g, after the cell density reached 4-5s v/v. They were then suspended in 2-2.5 volumes of cold buffer TB (0.2M Sucrose; O.lM KCl; O.lM MgC12; O.O25M EDTA; 0.05M Tris-HCl; pH 7.2) and broken with four strokes in a Potter equipped with a Teflon pestle. The
863
BIOCHEMICAL
Vol. 86, No. 3, 1979
AND BIOPHYSICAL RESEARCH COMMUNICATIONS
homogenate was centrifuged for 10 minutes at 15,000 g in a Sorvall The post mitochondrial supernatant was transferred ss-34 rotor. into a 50.2 Ti rotor (Beckman) and the ribosomes were pelleted for 3 hours at 49,000 rpm. The supernatant was discarded and the pellets resuspended in half the initial volume of buffer TB. This crude ribosome preparation was contaminated with polysaccharide, which was elimated by a centrifugation of 30 minutes at 39,000 rpm. The supernatant, containing most of the ribosomes, was centrifuged for 2 hours at 49,000 rpm. The ribosomal proteins were extracted with acetic acid (16) and precipitated with acetone (17). Residual ribosomal RNA was eliminated by incubation of the proteins with a mixture of pancreatic and T2 ribonucleases (6). Two-dimensional electrophoresis was performed according to Kaltschmidt and Wittmann were localized by autoradiography (18). The phosphoproteins and further analyzed by SDS-electrophoresis (19) on a 12-16% gradient of polyacrylamide gel according to Laemmli (20).
RESULTS AND DISCUSSION The two-dimensional the ribosomal
proteins
shown in Figure spots
could ~1, ~20,
after
the
lA.
was incubated showed that
diffuse
staining
radiography can therefore
were
gel spots
were
electrophoresis
cut
gels
disappeared
that
effectively the
out from the two-dimensional The results
864
used,
is five
namely
S3,
be detected in presence
bands
of the
were labelled
five
gel
and only
of migration.
pattern
obtained
and SDS electrophoresis,
in SDS gels.
these
from the
ribosomal data
also
proteins
the front
the
lB),
gel
to electrophoresis.
gave a similar
to correlate
electrophoresis
prior
be seen near
be concluded
autoradiography
could
a sample
pronase
the bands
could
of the
In order
with
were
(Fig.
that
proteins,
of the
proteins
bands
to confirm
phosphorylated
us to resolve
A photograph
of the k-ibosomal
In order
Results
spots.
radioactive
electrophoresis
effectively
67
enabled
by autoradiography
Five
2).
electrophosesis
When 32 PO4 labelled
~24.
of SDS (Fig.
It
into
be detected
sg,
material
gel
(Results
bands
Autonot
detected
shown).
by
phosphoproteins. by two-dimensional the gel
individual
labelled
and submitted
are summarized
to
in Table
1.
Vol. 86, No. 3, 1979
8lOCHEMlCAL
AND BIOPHYSICAL RESEARCH COMMUNICATIONS
b Two dimensional electrophoresis of total ribosomal proteins 1.2 mg according to Kaltschmidt and Wittmann (18). A: Photograph of the gel after staining. B: Autoradiography of the gel after labelling the proteins in Material and --in vivo with 32~14 as described Methods.
F=+
865
Vol.
86,
No.
BIOCHEMICAL
3, 1979
AND
BIOPHYSICAL
RESEARCH
Figure 2. SDS gel electrophoresis of ribosomal proteins vivo with 32~04, as described in Material and Methods. was carried out in 12-16% acrylsmide gradients according (20) A: Photograph of the gel. B: Autoradiogrsm.
The relative proteins protein (70%)
distribution
was also S3 accounted and that
determined for
itwaslocated
of radioactivity (Table
1).
the major
part
in the
866
small
It
COMMUNICATIONS
labelled in Electrophogsis to Laemmli
among the
five
can be seen that
of the
total
subunit.
radioactivity It
may be
BIOCHEMICAL
Vol. 86, No. 3, 1979
AND BIOPHYSICAL RESEARCH COMMUNICATIONS
TABLE1
Ribosomal
proteins
phosphorylated
Molecular
Protein
weight
% total
3.5
L24
15,500
16.5
s9
32,000
3
Ll7
42,000
5
s3
55,000
70
were
labelled
with
32P0
were prepared
--in
related
to protein
~6 of rat
weight
is definitely
higher
function
in ribosome
proteins
belongedto
(55,000
labelled.
The protein
to the
rate
ribosomal
was much less
than
for
results
are phosphorylated to all
organism
is highly
ribosomal
proteins
synchronythrough pathways useful
of Physarum system
in which
cell
its
molecular
However,
its
for
L24, were
weight
similar
and except
Sg had a molecular ~6.
However,
the
acidic
phosphorylation
S3. ribosomes
from
and further It
is
cycle
polycephalum to study
polycephalum
that
of interest
this
to note
phenomenon that
the phosphorylation
early
should
this
of The natural
in evolution.
and multiple
this
Physarum
confirm
and that
has appeared the
(2) although
(14).
subunit,
eukaryotes. primitive
subunits
The three
protein
in vivo,
ribosomal
purified
vs. 36,000).
protein
show that
and
as described in in parenthesis refer
may be equivalent.
the large
weakly
liver
liver
activity
viva
and anilyzed
Material and Methods. Numbers to numeration of proteins from
general
radioactivity
15,000
proteins
is
viva
L20
Cells
These
in
differentiation
make this
phenomenon
organism
a
further.
ACKNOWLEDGMENT This work was supported (Canada) and FCAC (Province
by grants of Qugbec).
867
from National
Research
Council
Vol.
86,
No.
3, 1979
BIOCHEMICAL
AND
BIOPHYSICAL
RESEARCH
COMMUNICATIONS
REFERENCES l2345678910ll121314151617181920-
Kabat, D. (1970) Biochemistry 2, 4160-4175. Gressner, A.M. and Wool, I.G. (1974) J. Biol. Chem. 249. 6917~6925. Rankine, A.U., Leader, D.P. and Coia, A.A. (1977) Biochem. Biophys. Acta 474, 293-307. Schiffmann, D. and Hors&, I. (1978) Eur. J. Biochem. 82, 91-95. Leader, D.P. and Coia, A.A. (1978) Biochem. Biophys. Acta 519, 213-223. Zinker, S. and Warner, J.R. (1976) J. Biol. Chem. 251, 1799-1807. Kaerlin, M., Horsk, I. (1976) Nature 259, 150-151. Blat, C. and Loeb, J.E. (1971) FEBS Lett I& 124-126. Cawthon, M.L., Bitte, L.F., Krystosed, A. and Kabat, D. (1974) J. Biol. Chem. 2@, 275-278. Rupp, R.G., Humphrey, R.M. and Shaeffer, J.R. (1976) Biochem. Biophys. Acta 2, 81-92. Eil, C. and Wool, I.G. (1973) J. Biol. Chem. 248, 5122-5129. Rubin, C.S. and Rosen, O.M. (1975) Ann. Rev. schem. 46, 831-887. Daniel, J.b. and Baldwin, H.M. (1964) In: uMethods in Cell Physiology'. Academic Press, N.Y. 9-41. Lemieux, G., Bglanger, G., Nicole, L. and Bellemare, G. (1978) Submitted for publication. Bersier, D. and Braun, R. (1974) Biochim. Biophys. Acta &I, 46x-471. Hardy, S.J.S., Kurland, C.G., Voynow, P. and Mora, G. (1969) Biochemistry 8, 2897-2905. Barritault, D., Expert-Bezaqon, A., Guerin, M.F. and Hayes, D. (1976) Eur. J. Biochem. 63, 131-135. Kaltschmidt, E. and Wittmann, H.G. (1970) Anal. Biochem. 36, 401-4 Horak, I. and Schiffmann, 0. (1977) Eur. J. Biochem. 79,?75-380. Laemmli, U.K. (1970) Nature g, 680-682.
868
.2.
