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Gene Review

MPP1  -  membrane protein, palmitoylated 1, 55kDa

Homo sapiens

Synonyms: 55 kDa erythrocyte membrane protein, AAG12, DXS552E, EMP55, MRG1, ...
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Disease relevance of MPP1


High impact information on MPP1

  • This study sought to develop a simple, reproducible assay, practical for screening genomic DNA samples for p55/G6PD genotypes, rapid clonality determination, and to determine the linkage relationship between these closely related loci [4].
  • 209 female and 207 male genomic DNA samples were analyzed for p55/G6PD genotype by ASPCR; 60% of females were heterozygous at one or both loci [4].
  • CD25 (Tac, p55), the alpha chain of the interleukin 2 receptor, is expressed on activated, but not quiescent, T cells [5].
  • The abundant expression of p55 mRNA, along with protein 4.1 mRNA, was evident in terminally differentiated human reticulocytes [1].
  • This fact may be partly explained by the observation that p55 is the most extensively palmitoylated protein of the erythrocyte membrane [1].

Biological context of MPP1


Anatomical context of MPP1

  • Using allele-specific polymerase chain reaction (PCR) assays for the JAK2 mutation and for the X-chromosomal clonality markers IDS and MPP1, we found that the percentage of granulocytes and platelets with JAK2-V617F was often markedly lower than the percentage of clonal granulocytes determined by IDS or MPP1 clonality assays in female patients [9].
  • Due to the presence of only one PDZ motif, MPP4 is part of the p55 subfamily, named after the major palmitoylated erythrocyte membrane protein p55/MPP1 [10].
  • Although p55 has many features consistent with known peripheral membrane proteins, its tight association with the plasma membrane is reminiscent of an integral membrane protein [1].
  • Our data provide new insights into how protein 4.1, glycophorin C, p55, and their non-erythroid homologues, interact with the cytoskeleton to exert their physiological effects [11].
  • 1. We estimate that the relative utilization of the three sites in normal membranes comprises 40% to p55, 40% to GPC/D, and 20% to band 3 [12].

Associations of MPP1 with chemical compounds

  • Human erythrocyte p55 is a peripheral membrane protein that contains three distinct domains in its primary structure: an N-terminal domain, an SH3 motif, and a C-terminal guanylate kinase domain [13].
  • In this report we provide evidence for the direct association of p55 with the NH2-terminal 30-kDa domain of protein 4.1, a key component of the erythroid membrane skeleton [14].
  • In this investigation, synthetically tagged peptides and bacterially expressed proteins were used to map the protein 4.1 binding site on human erythroid glycophorin C, a transmembrane glycoprotein, and on human erythroid p55, a palmitoylated peripheral membrane phosphoprotein [11].

Physical interactions of MPP1


Other interactions of MPP1

  • As MPP1 and CRYAB are also among the 14 genes differentially expressed in all three of the drug-resistant sublines, they represent the strongest candidates for resistance against DNA-damaging drugs [16].
  • On a stoichiometric basis, the reduction in glycophorin C (about 80%) was concomitant to the lack of p55 in RBCs devoid of protein 4 [13].
  • 4.1R promotes the formation of a ternary complex with GPC and p55 through its 30 kDa membrane-binding domain [17].
  • This protein, p55, is copurified during the isolation of dematin, an actin-bundling protein of the erythrocyte membrane cytoskeleton [1].
  • Finally, promoter activity measurements of the region immediately upstream of the p55 gene, which contains several cis-elements commonly found in housekeeping genes, suggest that a CpG island may be associated with the p55 gene expression in vivo [18].

Analytical, diagnostic and therapeutic context of MPP1

  • RT-PCR of p55 mRNA from a patient with acute megakaryoblastic CML revealed a 69 base pair deletion in the PDZ domain, corresponding to exon 5 of the p55 gene [2].


  1. Molecular identification of a major palmitoylated erythrocyte membrane protein containing the src homology 3 motif. Ruff, P., Speicher, D.W., Husain-Chishti, A. Proc. Natl. Acad. Sci. U.S.A. (1991) [Pubmed]
  2. Exon skipping truncates the PDZ domain of human erythroid p55 in a patient with chronic myeloid leukemia in acute megakaryoblastic blast crisis. Ruff, P., Chishti, A.H., Grimm, E., Bischoff, D., Kim, A.C. Leuk. Res. (1999) [Pubmed]
  3. Autoantibodies from patients with idiopathic ataxia bind to M-phase phosphoprotein-1 (MPP1). Fritzler, M.J., Kerfoot, S.M., Feasby, T.E., Zochodne, D.W., Westendorf, J.M., Dalmau, J.O., Chan, E.K. J. Investig. Med. (2000) [Pubmed]
  4. Rapid determination of clonality by detection of two closely-linked X chromosome exonic polymorphisms using allele-specific PCR. Liu, Y., Phelan, J., Go, R.C., Prchal, J.F., Prchal, J.T. J. Clin. Invest. (1997) [Pubmed]
  5. Combined use of an immunotoxin and cyclosporine to prevent both activated and quiescent peripheral blood T cells from producing type 1 human immunodeficiency virus. Bell, K.D., Ramilo, O., Vitetta, E.S. Proc. Natl. Acad. Sci. U.S.A. (1993) [Pubmed]
  6. Discrimination of polycythemias and thrombocytoses by novel, simple, accurate clonality assays and comparison with PRV-1 expression and BFU-E response to erythropoietin. Liu, E., Jelinek, J., Pastore, Y.D., Guan, Y., Prchal, J.F., Prchal, J.T. Blood (2003) [Pubmed]
  7. Dyskeratosis congenita caused by a 3' deletion: germline and somatic mosaicism in a female carrier. Vulliamy, T.J., Knight, S.W., Heiss, N.S., Smith, O.P., Poustka, A., Dokal, I., Mason, P.J. Blood (1999) [Pubmed]
  8. The gene encoding the palmitoylated erythrocyte membrane protein, p55, originates at the CpG island 3' to the factor VIII gene. Metzenberg, A.B., Gitschier, J. Hum. Mol. Genet. (1992) [Pubmed]
  9. Acquisition of the V617F mutation of JAK2 is a late genetic event in a subset of patients with myeloproliferative disorders. Kralovics, R., Teo, S.S., Li, S., Theocharides, A., Buser, A.S., Tichelli, A., Skoda, R.C. Blood (2006) [Pubmed]
  10. Cloning and characterization of the human retina-specific gene MPP4, a novel member of the p55 subfamily of MAGUK proteins. Stöhr, H., Weber, B.H. Genomics (2001) [Pubmed]
  11. Identification of the protein 4.1 binding interface on glycophorin C and p55, a homologue of the Drosophila discs-large tumor suppressor protein. Marfatia, S.M., Leu, R.A., Branton, D., Chishti, A.H. J. Biol. Chem. (1995) [Pubmed]
  12. Identification of the membrane attachment sites for protein 4.1 in the human erythrocyte. Hemming, N.J., Anstee, D.J., Staricoff, M.A., Tanner, M.J., Mohandas, N. J. Biol. Chem. (1995) [Pubmed]
  13. Evidence that red blood cell protein p55 may participate in the skeleton-membrane linkage that involves protein 4.1 and glycophorin C. Alloisio, N., Dalla Venezia, N., Rana, A., Andrabi, K., Texier, P., Gilsanz, F., Cartron, J.P., Delaunay, J., Chishti, A.H. Blood (1993) [Pubmed]
  14. In vitro binding studies suggest a membrane-associated complex between erythroid p55, protein 4.1, and glycophorin C. Marfatia, S.M., Lue, R.A., Branton, D., Chishti, A.H. J. Biol. Chem. (1994) [Pubmed]
  15. Phosphatidylinositol-4,5-Biphosphate (PIP(2)) Differentially Regulates the Interaction of Human Erythrocyte Protein 4.1 (4.1R) with Membrane Proteins. An, X., Zhang, X., Debnath, G., Baines, A.J., Mohandas, N. Biochemistry (2006) [Pubmed]
  16. Candidate genes for cross-resistance against DNA-damaging drugs. Wittig, R., Nessling, M., Will, R.D., Mollenhauer, J., Salowsky, R., Münstermann, E., Schick, M., Helmbach, H., Gschwendt, B., Korn, B., Kioschis, P., Lichter, P., Schadendorf, D., Poustka, A. Cancer Res. (2002) [Pubmed]
  17. Regulation of protein 4.1R interactions with membrane proteins by Ca2+ and calmodulin. Nunomura, W., Takakuwa, Y. Front. Biosci. (2006) [Pubmed]
  18. Complete genomic organization of the human erythroid p55 gene (MPP1), a membrane-associated guanylate kinase homologue. Kim, A.C., Metzenberg, A.B., Sahr, K.E., Marfatia, S.M., Chishti, A.H. Genomics (1996) [Pubmed]
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