Disease relevance of GPM6B

• We evaluated 48 archival cases of acute erythroleukemia and divided them into 3 groups: M6a, corresponding to the traditional French-American-British M6 category; M6b, which is pure erythroleukemia; and M6c, in which myeloblasts and pronormoblasts each account for more than 30% of cells by the French-American-British exclusion criteria [1].
• The recent WHO classification has a category of acute myeloid leukemia not otherwise categorized, which includes acute erythroid leukemia (M6) of two subtypes: M6a-erythroleukemia (erythroid/myeloid) and M6b-pure erythroid leukemia [2].
• RESULTS: Fifty-three patients met the criteria of M6a subtype of the WHO classification, and 2 were classified as having pure erythremia (M6b); 7 cases could not be classified according to the WHO criteria [2].
• Patients with this type of leukemia traditionally have been treated with a standard myeloid protocol, with a wide variation in prognosis between M6a, which has a similar prognosis to acute myelogenous leukemias, and M6b, with an extremely poor outcome despite aggressive therapy [3].
• Cotransfection experiments suggest a physical interaction of M6B and mutant PLP, when retained in the endoplasmic reticulum, that may also contribute to oligodendrocyte dysfunction in Pelizaeus-Merzbacher disease [4].

Psychiatry related information on GPM6B

• Mutation analysis of the M6b gene in patients with Rett syndrome [5].

High impact information on GPM6B

• Two promoters and alternative exons yield at least eight M6B proteins and polypeptides, differentially expressed in neurons and oligodendrocytes [4].
• Using the multiplex amplifiable probe hybridization (MAPH) technique, we looked simultaneously for intragenic rearrangements along the PLP1 gene (exonic and regulatory regions) and for rearrangements in the GPM6B candidate gene (a member of the proteolipid protein family) [6].
• The accumulation of A1(6)G1Fo and increased A2G2Fo(6)F levels were accompanied by decreased levels of the high mannose-type sugar chains, M5A, M6B, M8A, and M9A [7].
• Because patients with M6b and M6c have increased numbers of pronormoblasts in their bone marrow and past chemotherapeutic attempts have failed, chemotherapy directed at these cells is appropriate [3].
• P-glycoprotein expression and multiple cytogenetic anomalies most probably contribute to the resistance to chemotherapy and poor survival characteristic of the patients with M6b (mean survival, 3.15 +/- 4.2 mo) and M6c (mean survival, 10.5 +/- 12.7 mo) [3].

Anatomical context of GPM6B

• Recent cotransfection experiments suggest a protein-protein interaction of M6B and mutant PLP1 that may contribute to oligodendrocyte dysfunction in PMD [8].
• 2. The encoded M6B protein is a member of a novel proteolipid family that also includes other major brain myelin components like the proteolipid protein (PLP) [8].
• Compared to M6A, both the M6B (P< 0.0001) and M6C (P< 0.0001) variants showed a statistically significant increase in the percentage of bone marrow erythroid cells, proerythroblasts, and the proerythroblasts/erythroid ratios [9].
• To date, three different gene products, DMalpha/DM-20/PLP, DMbeta/M6a, and DMgamma/M6b, have been isolated from certain primitive fish species, mouse, and human central nervous system (CNS) [10].

Associations of GPM6B with chemical compounds

• The minor metabolites were identified, by LC-MS/MS comparison with synthetic standards or by NMR, as acyl glucuronide (M1), sulfoxide (M2), 25-hydroxy (a phenol, M3), 21-hydroxy (diastereomers of a benzylic alcohol, M5a and M5b), and 36-hydroxy (diastereomers of a methyl alcohol, M6a and M6b) analogs of montelukast [11].

Other interactions of GPM6B

• Chemotherapeutic regimens induced remission in all treated patients in the M6a and M6c groups but did not appear to affect the M6b group [1].
• This analysis highlighted both known differences in serum and citrated plasma such as fibrinogens, and reproducible differences in peptide abundances from proteins such as soluble activin receptor-like kinase 7b and glycoprotein m6b [12].

Analytical, diagnostic and therapeutic context of GPM6B

• We have isolated partial human cDNA and genomic clones encoding M6a and M6b and have characterized them by restriction mapping, Southern hybridization with cDNA probes, and sequence analysis [13].
• Mutations in the GRPR gene and M6b genes were excluded by sequence analysis [14].

References