Primary Information |
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| BoMiProt ID | Bomi279 |
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| Protein Name | 55 kDa erythrocyte membrane protein |
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| Organism | Bos taurus |
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| Uniprot ID | Q17QN6 |
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| Milk Fraction | Exosome |
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| Ref Sequence ID | NP_001068952.1 |
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| Aminoacid Length | 466 |
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| Molecular Weight | 52184 |
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| FASTA Sequence |
Download |
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| Gene Name | MPP1 |
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| Gene ID | 510998 |
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| Protein Existence Status | Reviewed: Experimental evidence at protein level |
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Secondary Information |
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| Presence in other biological fluids/tissue/cells | ubiquitously expressed |
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| Protein Function | Also known as MPP1 which is required for cell growth and maintenance; palmitoylated protein which is required for platelet activation; prototypical member of a family of signaling proteins termed MAGUKs (membrane associated guanylate kinase homologues); scaffolding protein in erythrocytes stabilizing the actin cytoskeleton to the plasma membrane; regulates neutrophil polarity, and functions as a positive upstream effector of Akt phosphorylation. |
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| Biochemical Properties | In mature erythrocytes, p55 forms a ternary complex with
protein 4.1R and glycophorin C with implications in the regulation
of cell shape and membrane stability; The predicted amino acid sequence of p55 does not contain any consensus sequence corresponding to the catalytic domains of protein kinases but does contain a conserved sequence found in the noncatalytic domains of oncogene-encoded tyrosine kinases. This conserved src homology 3 (SH-3) motif appears to suppress the tyrosine kinase activity of various oncoproteins and has also been found in several plasma membrane associated proteins involved in signal transduction. |
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| PTMs | Palmitoylation - four cysteine residues in p55, including one in
the SH-3 motif, that may provide potential sites for palmitoylation |
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Site(s) of PTM(s)
N-glycosylation,
O-glycosylation,
Phosphorylation
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| Predicted Disorder Regions | NA |
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| DisProt Annotation | |
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| TM Helix Prediction | No TM helices |
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| Significance of PTMs | enhances the
hydrophobicity of a protein,;
regulate protein trafficking, sorting, stability, and activity; functions as a regulatory mechanism or molecular switch, directing
protein-lipid and protein-protein interactions and plays a role in
the regulation of cellular responses to external stimuli |
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| Additional Comments | Slower dynamics of palmitoylation in erythrocytes from patients suffering from chronic myelogenous leukemia, which are less stable than normal erythrocytes |
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| Bibliography | 1. Quinn, B. J. et al. (2009) ‘Erythrocyte scaffolding protein p55/MPP1 functions as an essential regulator of neutrophil polarity.’, Proceedings of the National Academy of Sciences of the United States of America, 106(47), pp. 19842–7. doi: 10.1073/pnas.0906761106.
2. Ruff, P., Speicher, D. W. and Husain-Chishti, A. (1991) ‘Molecular identification of a major palmitoylated erythrocyte membrane protein containing the src homology 3 motif.’, Proceedings of the National Academy of Sciences of the United States of America, 88(15), pp. 6595–9. doi: 10.1073/pnas.88.15.6595.
3. Dowal, L. et al. (2011) ‘Proteomic analysis of palmitoylated platelet proteins’, Blood, 118(13), pp. e62–e73. doi: 10.1182/blood-2011-05-353078. 4.Das AK, Kundu M, Chakrabarti P, Basu J. Fatty acylation of a 55 kDa membrane protein of human erythrocytes. Biochim Biophys Acta. 1992 Jul 27;1108(2):128-32. doi: 10.1016/0005-2736(92)90016-f. PMID: 1637837. 5.Ruff P, Speicher DW, Husain-Chishti A. Molecular identification of a major palmitoylated erythrocyte membrane protein containing the src homology 3 motif. Proc Natl Acad Sci U S A. 1991 Aug 1;88(15):6595-9. doi: 10.1073/pnas.88.15.6595. PMID: 1713685; PMCID: PMC52133. |
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