TY  - JOUR
A1  - Singh, Jasbir
A1  - Dani, Harinder M.
A1  - Sharma, Reeta
A1  - Steinberg, Pablo
T1  - Inhibition of the biosynthesis of SRP polypeptides and secretory proteins by aflatoxin B-1 can disrupt protein targeting
JF  - Cell biochemistry and function
N2  - Cell culture and western blotting studies revealed that aflatoxin B-1 (AFB(1)) inhibits the biosynthesis of two of the constituent polypeptides of signal recognition particle (SRP) (SRP54 and 72). SRP escorts polyribosomes carrying signal peptides from free form in the cytosol to the bound form on endoplasmic reticulum (ER) membrane during protein targeting. These effects of AFB(1) on SRP biosynthesis may inhibit the formation of functional SRP Our experiments have further shown that AFB(1) also inhibits the biosynthesis/translocation of a secretory protein, preprolactin, which fails to appear in the lumen of ER consequent to the treatment with this hepatocarcinogen. The results of the experiments presented in this article therefore enable us to infer for the first time that aflatoxin B-1 may inhibit the functioning of SRP as an escort and deplete the ER of polyribosomes for secretory protein synthesis. As these secretory proteins are important components of the plasma membrane, gap junctions and intercellular matrix, their absence from these locations could disturb cell to cell communication leading to tumorigenesis.
KW  - aflatoxin B-1
KW  - SRP
KW  - protein targeting
KW  - protein translocation
KW  - western blotting
Y1  - 2005
U6  - https://doi.org/10.1027/cbf.1285
SN  - 0263-6484
VL  - 24
SP  - 507
EP  - 510
PB  - Wiley
CY  - Chichester
ER  - 
TY  - JOUR
A1  - Singh, Jasbir
A1  - Singh, S.
A1  - Dani, H. M.
A1  - Sharma, Reeta
A1  - Steinberg, Pablo
T1  - Interactions of aflatoxin B-1 with SRP components can disrupt protein targeting
N2  - Spectrofluorimetric studies have revealed that aflatoxin B-1 (AFB(1)) interacts with signal recognition particle (SRP), which acts as an escort for polyribosomes with signal peptides to be transported and bound to the cytoplasmic face of the endoplasmic reticulum (ER). We further report that the binding of AFB(1) to SRP is selective as it only binds to two (SRP9 and 14) out of its three constituent polypeptides studied. Binding of AFB(1) to proteins is known to alter their conformations. Interactions of AFB(1) with SRP polypeptides may generate structural and functional alterations in this particle and hinder secretory protein synthesis. Copyright (C) 2004 John Wiley Sons, Ltd
Y1  - 2005
SN  - 0263-6484
ER  -