Alkaline phosphatase isozymes in the midgut of silkworm: purification of high pH-stable microvillus and labile cytosolic enzymes

Identification of novel Cry1Ac binding proteins in midgut membranes from Heliothis virescens using proteomic analyses

“…There is direct evidence that Cry1Ac binds ALPs in blots (McNall and Adang, 2003) and in native state (English and Readdy, 1989;Sangadala et al, 1994) and that they can be functional Cry toxin receptors (Fernandez et al, 2006). In B. mori, membrane-bound (mALP) and soluble (sALP) forms of alkaline phosphatase have been described (Okada et al, 1989). When representative spots that bound Cry1Ac and mALP antisera were picked for PMF analysis, high probability matches to the membrane-bound form of B. mori ALP in the databases were obtained.…”

“…Based on the molecular sizes and pI values reported for insect midgut mALP (Okada et al, 1989;Takesue et al, 1989;McNall and Adang, 2003), we predicted that the Cry1Ac-binding spots at 65-kDa were forms of HvALP. To test this possibility, 2D blots of BBMV proteins were probed with anti-mALP sera (Azuma and Eguchi, 1989).…”

Functional expression in insect cells of glycosylphosphatidylinositol-linked alkaline phosphatase from Aedes aegypti larval midgut: A Bacillus thuringiensis Cry4Ba toxin receptor

“…The s-ALP is found exclusively in the cavity of goblet cells and in the apical region of the midgut ; whereas, m-ALP is localized in the brush border membrane of columnar cells and particularly restricted to the middle and posterior midgut. Moreover, s-and m-ALPs show distinct differences in enzymatic activity (such as optimal pH) and also the structure of sugar side chain (Okada et al, 1989;Azuma et al, 1991), suggesting that they perform different functions in vivo.…”

Tandem duplication of alkaline phosphatase genes and polymorphism in the intergenic sequence in Bombyx mori

“…The spatial patterns of their expression are different; mALP is expressed on the brush border of the columnar cells and sALP in the cavity of the goblet cells (Eguchi et al 1972;Azuma and Eguchi 1989). In addition, studies with the purified isozymes indicate that they differ functionally in some respects, for instance, in pH optimum, inhibition by amino acids, and in the structures of their attached sugar chains (Okada et al 1989;Eguchi et al 1990;Azuma et al 1991;Yamamoto et al 1991). On the other hand, the temporal patterns of their transcription are very similar; the mRNAs appear first just before hatching, reach a maximum at the end of the fifth-instar larval stage, and disappear rapidly during metamorphosis, suggesting they have important roles in digestion or nutrient transport (Itoh et al 2000).…”