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Table 2 Differentially regulated phosphopeptides in SS RBCs in response to MEK1/2 inhibitor U0126

From: Proteomic analysis of ERK1/2-mediated human sickle red blood cell membrane protein phosphorylation

Protein description

Modified peptide sequence

AA vs SS: Fold Change (p-value)

SS vs SS+U0126: Fold change (p-value)

SS vs SS+ERK2: Fold change (p-value)

SS+U0126 vs SS+U0126+ERK2: Fold change (p-value)

AA vs AA+ERK2: fold change (p-value)

60S acidic ribosomal protein P2

KEES*EES*DDDMGFGLFD

4.8 (7.24E-20)

−2.1 (3.61E-08)

NS

NS

NS

Adenylyl cyclase-associated protein 1

SGPKPFSAPKPQTS*PSPK

NS

−4.8 (2.00E-03)

NS

5.3 (2.00E-04)

NS

Alpha-adducin

QKGS*EENLDEAR

2.5 (2.43E-33)

−4.1 (2.80E-45)

NS

2.4 (1.25E-11)

NS

Beta-adducin

ETAPEEPGS*PAKS*APAS*PVQSPAK

5.6 (3.72E-28)

−1.9 (3.87E-09)*

NS

NS

2.4 (4.21E-06)*

Beta-adducin

ETAPEEPGSPAKS*APAS*PVQSPAK

NS

−1.8 (1.80E-02)*

NS

1.8 (3.00E-02)

1.8 (2.00E-02)*

Beta-adducin

TESVTSGPMSPEGSPSKS*PSK

NS

−1.9 (3.00E-02)

NS

1.9 (3.00E-03)

NS

Dematin

QPLTSPGSVS*PSR

7.9 (8.63E-05)

−4.4 (1.00E-03)

NS

NS

NS

E3 ubiquitin-protein ligase UBR4

T*SPADHGGSVGSESGGSAVDSVAGEHSVSGR

3.6 (1.55E-18)

−1.8 (1.02E-07)

NS

NS

NS

Eukaryotic translation initiation factor 4B

SQS*SDTEQQSPTSGGGK

5.6 (9.74E-06)

−2.5 (4.00E-03)

NS

2.0 (2.00E-02)

NS

facilitated glucose transporter member 1

QGGAS*QSDKTPEELFHPLGADSQV

5.0 (7.45E-10)

−3.4 (7.99E-08)

NS

NS

NS

Glycophorin-A

KS*PSDVKPLPSPDTDVPLSSVEIENPETS*DQ

7.7 (9.74E-07)

−1.9 (2.10E-02)

NS

NS

2.0 (5.00E-03)

Glycophorin-A

KSPSDVKPLPS*PDT*DVPLS*SVEIENPETSDQ

10.2 (1.05E-06)

−2.3 (5.00E-03)

NS

NS

2.1 (8.04E-04)

Glycophorin-A

S*PS*DVKPLPSPDTDVPLSSVEIENPETS*DQ

6.3 (9.08E-07)

−2.0 (1.60E-02)

NS

NS

1.9 (3.10E-02)

Glycophorin-A

S*PS*DVKPLPSPDTDVPLSSVEIENPETSDQ

6.3 (9.08E-07)

−2.0 (8.00E-03)

NS

NS

NS

Glycophorin-A

SPSDVKPLPS*PDT*DVPLS*SVEIENPETSDQ

7.4 (8.28E-06)

−1.9 (2.90E-02)

NS

NS

1.9 (6.00E-03)

Glycophorin-A

SPSDVKPLPS*PDT*DVPLSSVEIENPETSDQ

5.0 (0.00E+00)

−2.0 (2.13E-07)

NS

NS

NS

Glycophorin-A

SPSDVKPLPSPDT*DVPLS*SVEIENPETSDQ

5.0 (0.00E+00)

−1.8 (4.80E-02)

NS

NS

NS

Glycophorin-A

SPSDVKPLPSPDT*DVPLSSVEIENPETSDQ

5.0 (0.00E+00)

−2.0 (2.59E-21)

NS

NS

NS

Glycophorin-A

SPSDVKPLPSPDTDVPLS*S*VEIENPETSDQ

5.1 (3.49E-06)

−2.2 (3.00E-03)

NS

NS

2.7 (7.97E-05)

Glycophorin-A

SPSDVKPLPSPDTDVPLSS*VEIENPETSDQ

NS

−1.9 (3.30E-07)

NS

NS

NS

Glycophorin-A

SPSDVKPLPSPDTDVPLSSVEIENPET*SDQ

NS

−1.9 (1.82E-13)

NS

NS

NS

Glycophorin-A

SPSDVKPLPSPDTDVPLSSVEIENPETS*DQ

NS

−1.8 (4.00E-03)

NS

NS

NS

Leucine-rich repeats and immunoglobulin-like domains protein 2

T*HPETIIALRGMNVTLTCTAVSSSDSPMST*VWR

NS

−2.9 (1.27E-23)

NS

1.8 (2.65E-05)

NS

Leucine-zipper-like transcriptional regulator 1

MAGPGST*GGQIGAAALAGGAR

88.6 (1.70E-02)

−6.5 (4.50E-02)

NS

6.7 (4.54E-06)

NS

Lipin-2

S*GGDETPSQSSDISHVLETETIFTPSSVK

3.0 (1.56E-08)

−1.9 (3.37E-04)

NS

NS

NS

Metabotropic glutamate receptor 7

LSHKPSDRPNGEAKT*ELCENVDPNS*PAAK

2.4 (1.61E-15)

−1.9 (2.95E-09)

NS

NS

2.3 (7.98E-15)

Proteasome subunit alpha type-3

ESLKEEDES*DDDNM

2.8 (4.14E-11)

−1.8 (5.42E-06)

NS

NS

NS

Protein MICAL-2

VS*S*GIGAAAEVLVNLY*MNDHRPKAQAT*SPDLESMRK

NS

−4.1 (8.44E-05)

NS

NS

NS

Protein Wnt-16

HERWNCMITAAATTAPMGASPLFGYELS*SGTK

−2.2 (5.13E-05)

−2.0 (1.90E-02)

NS

NS

NS

Spectrin beta chain, erythrocyte

LS*SS*WESLQPEPSHPY

3.5 (4.17E-13)

−1.8 (5.56E-05)

NS

NS

2.0 (9.30E-11)

Spectrin beta chain, erythrocyte

QIAERPAEETGPQEEEGETAGEAPVS*HHAATER

2.1 (6.00E-03)

−2.4 (5.77E-04)

NS

NS

NS

Transmembrane protein 151B

SPPGS*AAGES*AAGGGGGGGGPGVSEELTAAAAAAAADEGPAR

NS

−2.9 (3.91E-05)

NS

NS

NS

U3 small nucleolar RNA-associated protein 15

VVHS*FDYAAS*ILSLALAHEDETIVVGMTNGILS*VKHR

NS

−2.9 (7.39E-11)

NS

2.2 (6.08E-05)

2.1 (9.39E-14)

Uncharacterized protein LOC388588

DGVS*LGAVS*STEEASR

NS

−1.8 (9.99E-05)

NS

NS

2.2 (2.40E-09)

Uncharacterized protein LOC388588

DGVS*LGAVSST*EEASR

2.2 (2.00E-02)

−1.8 (4.90E-02)

NS

NS

NS

UV excision repair protein RAD23 homolog A

EDKS*PSEESAPTTSPESVSGSVPSSGSSGR

5.0 (6.40E-38)

−2.0 (1.96E-14)

NS

NS

2.2 (4.13E-32)

  1. 36 unique phosphorylated peptides were statistically down-regulated in SS RBCs upon treatment with the MEK1/2 inhibitor U0126 (SS vs SS+U0126). Of these 36, 8 phosphopeptides had their levels increased back to near basal levels upon exogenous addition of active ERK2 (SS+U0126 vs SS+U0126+ERK2). Thirteen of these phosphorylated peptides were also observed to be increased in AA RBCs upon exogenous addition of active ERK2 (AA vs AA+ERK2), suggesting specificity of downstream ERK activity. p-values < 0.05 indicate the statistically significant variances associated with differences within triplicates for that particular comparison. Biological variances associated with differences within groups are not included in these p-values. (*) indicates previously reported values[18]. NS, which refers to non-significant, indicates that a statistically significant change (based on 1.75 fold-changes and p-value < 0.05) was not measured.