Localization of a novel 252-kDa plasma membrane protein that binds Cry1A toxins in the midgut epithelia of Bombyx mori

Delwer M. Hossain, Yasuyuki Shitomi, Yohei Nanjo, Daisuke Takano, Tadayuki Nishiumi, Tohru Hayakawa, Toshiaki Mitsui, Ryoichi Sato, Hidetaka Hori

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


We previously demonstrated that a novel 252-kDa protein (P252) isolated from brush border membranes (BBM) of Bombyx mori, hybrid ShureiXShogetsu, specifically bound Cry1Aa, Cry1Ab and Cry1Ac toxins with a Kd of 29, 179 and 20 nM, respectively. P252 was found in a Triton X-100 - soluble fraction of BBM from first, third and fifth instar larvae, suggesting that it may be an important element of midgut epithelial cell membranes. P252 was not partitioned into a Triton X-100-insoluble BBM fraction and nearly identical partitioning of P252 was observed using detergents CHAPS and Igepal. These results suggested that P252 localized in non-raft regions of BBM. Immunofluorescence analysis using anti-P252 antiserum demonstrated the existence of P252 in BBMV. Cy3-labeled Cry1Aa, Cry1Ab and Cry1Ac were shown to bind to BBMV, and the addition of anti-P252 antiserum reduced the number of BBMV showing Cy3 fluorescence by 30%. This clearly suggested an important role for P252 in Cry1A binding to BBMV. CD spectra of a mixture of purified P252 with either Cry1Aa, Cry1Ab or Cry1Ac were compared with those of respective free Cry1A toxins and only one of the mixtures (Cry1Aa/P252) was shown to be significantly changed compared to that of native Cry1Aa.

Original languageEnglish
Pages (from-to)125-135
Number of pages11
JournalApplied Entomology and Zoology
Issue number1
Publication statusPublished - Feb 2005
Externally publishedYes


  • Bacillus thuringiensis
  • Cy3 labeled Cry1A toxins
  • Insecticidal toxin
  • Midgut epithelial cell membrane

ASJC Scopus subject areas

  • Insect Science


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