Disease relevance of MAP7

• Immunolabeling of skin sections indicated that E-MAP-115 is predominantly expressed in the suprabasal layers of the normal epidermis and, in agreement with this observation, is relatively abundant in squamous cell carcinomas but barely detectable in basal cell carcinomas [1].

High impact information on MAP7

• We show here that binding of E-MAP-115 to microtubules is regulated by phosphorylation during the cell cycle [2].
• Expression levels of E-MAP-115, a microtubule-associated protein that stabilizes microtubules, increase with epithelial cell polarization and differentiation (Masson and Kreis, 1993) [2].
• These results suggest that phosphorylation of E-MAP-115 is a prerequisite for increasing the dynamic properties of the interphase microtubules which leads to the assembly of the mitotic spindle at the onset of mitosis [2].
• A fraction of E-MAP-115 from HeLa cells released from a block at the G1/S boundary runs with higher apparent molecular weight on SDS-PAGE, with a peak correlating with the maximal number of cells in early stages of mitosis [2].
• E-MAP-115 from nocodazole-arrested mitotic cells, which can be obtained in larger amounts, displays identical modifications and was used for further biochemical characterization [2].

Biological context of MAP7

• Haplotypes C-T-T-T in MAP7 and T-C-C in PEX7 were significantly associated with increases in concentration of HbF, both showing strong dominance [3].
• We then evaluated the involvement of MAP7 in SD by further screening of the gene in several patients with a similar phenotype [4].
• The 6p11.2 breakpoint mapped very close to the centromere, and the 6q23.3 breakpoint localized in the ninth intron of the MAP7 gene [4].
• Overexpression of this domain of E-MAP-115 by transfection of fibroblasts lacking significant levels of this protein with its cDNA renders microtubules stable to nocodazole [5].
• Upregulation and redistribution of E-MAP-115 (epithelial microtubule-associated protein of 115 kDa) in terminally differentiating keratinocytes is coincident with the formation of intercellular contacts [1].

Anatomical context of MAP7

• In HeLa cells, E-MAP-115 is preferentially associated with subdomains or subsets of perinuclear microtubules [5].
• Identification and molecular characterization of E-MAP-115, a novel microtubule-associated protein predominantly expressed in epithelial cells [5].
• In Caco-2 cells, labeling for E-MAP-115 increases when they polarize and form blisters [5].
• The mechanism whereby E-MAP-115 would redistribute to and stabilize cortical microtubules used for the polarized transport of vesicles towards the plasma membrane, where important reorganizations take place upon stratification, is discussed [1].
• The reported specific localization of E-MAP-115 to the spermatid manchette strongly supports its role as a regulator of cell polarization [6].

Associations of MAP7 with chemical compounds

• E-MAP-115 has two highly charged regions with predicted alpha-helical structure, one basic with a pI of 10.9 in the NH2-terminal domain and one neutral with a pI of 7.6 immediately following the PAPA region in the acidic COOH-terminal half of the molecule [5].

Analytical, diagnostic and therapeutic context of MAP7

• In primary keratinocytes whose terminal differentiation was induced by increasing the Ca2+ concentration of the medium, E-MAP-115 expression significantly increased during the first day, as observed by northern and western blot analysis [1].
• Parallel immunofluorescence studies showed an early redistribution of E-MAP-115 from microtubules with a paranuclear localization to cortical microtubules organized in spike-like bundles facing intercellular contacts [1].
• In the Western and Northern blot analysis, a distinct stage-dependent expression of a single E-MAP-115 polypeptide and two mRNA species (3.4 and 2.4 kb) could be identified [6].

References