Combined effect of Cameo2 and CBP on the cellular uptake of lutein in the silkworm, Bombyx mori.
Formation of yellow-red color cocoons in the silkworm, Bombyx mori, occurs as the result of the selective delivery of carotenoids from the midgut to the silk gland via the hemolymph. This process of pigment transport is thought to be mediated by specific cellular carotenoids carrier proteins. Previous studies indicated that two proteins, Cameo2 and CBP, are associated with the selective transport of lutein from the midgut into the silk gland in Bombyx mori. However, the exact roles of Cameo2 and CBP during the uptake and transport of carotenoids are still unknown. In this study, we investigated the respective contributions of these two proteins to lutein and β-carotene transport in Bombyx mori as well as commercial cell-line. We found that tissues, expressed both Cameo2 and CBP, accumulate lutein. Cells, co-expressed Cameo2 and CBP, absorb 2 fold more lutein (P<0.01) than any other transfected cells, and the rate of cellular uptake of lutein was concentration-dependent and reached saturation. From immunofluorescence staining, confocal microscopy observation and western blot analysis, Cameo2 was localized at the membrane and CBP was expressed in the cytosol. What's more, bimolecular fluorescence complementation analysis showed that these two proteins directly interacted at cellular level. Therefore, Cameo2 and CBP are necessarily expressed in midguts and silk glands for lutein uptake in Bombyx mori. Cameo2 and CBP, as the membrane protein and the cytosol protein, respectively, have the combined effect to facilitate the cellular uptake of lutein.
State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China ; College of Animal Science and Technology, Southwest University, Chongqing, China.
Wei
W
Wang
State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China.
Mao-Hua
MH
Huang
State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China.
Xiao-Long
XL
Dong
State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China.
Chun-Li
CL
Chai
State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China.
Cai-Xia
CX
Pan
State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China.
Hui
H
Tang
State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China.
Yan-Hong
YH
Chen
State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China ; Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China.
Fang-Yin
FY
Dai
State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China ; Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China.
Min-Hui
MH
Pan
State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China ; Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China.
Cheng
C
Lu
D000595:Amino Acid Sequence; D000704:Analysis of Variance; D000818:Animals; D001692:Biological Transport / Q000502:physiology; D015153:Blotting, Western; D012831:Bombyx / Q000378:metabolism* / Q000502:physiology; D017931:DNA Primers / Q000235:genetics; D005455:Fluorescent Antibody Technique; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D014975:Lutein / Q000378:metabolism*; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D010858:Pigmentation / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019207:beta Carotene / Q000378:metabolism
D017931:DNA Primers; D019476:Insect Proteins; D019207:beta Carotene; D014975:Lutein