RRC ID 51533
Author He B, Zhang J, Wang Y, Li Y, Zou X, Liang B.
Title Identification of cytochrome b5 CYTB-5.1 and CYTB-5.2 in C. elegans; evidence for differential regulation of SCD.
Journal Biochim Biophys Acta Mol Cell Biol Lipids
Abstract Unsaturated fatty acids (UFAs) play crucial roles in living organisms regarding development, energy metabolism, stress resistance, etc. The biosynthesis of UFAs starts from the introduction of the first double bond by stearoyl-CoA desaturase (SCD), converting saturated fatty acids (SFAs) to monounsaturated fatty acids (MUFAs). This desaturation is considered to be an aerobic process that requires cytochrome b5 reductase, cytochrome b5 and SCD. However, this enzyme system remains elusive in Caenorhabditis elegans. Here, we show that inactivation by RNAi knockdown or mutation (gk442189) of putative cytochrome b5 genes cytb-5.1 led to reduced conversion of C18:0 to C18:1(n-9) by SCD desaturases FAT-6/7 in C. elegans. On the contrary, cytb-5.2RNAi and cytb-5.2(gk113588) mutant worms showed decreased conversion of C16:0 to C16:1(n-7) by FAT-5 desaturase. Dietary supplementation with C18:1(n-9) and C18:2(n-6) also showed that CYTB-5.1 is likely required for the activity of FAT-6/7 desaturases, but not for FAT-1 to FAT-4 desaturases. Interestingly, co-immunoprecipitation (Co-IP) demonstrated that either FAT-7 or FAT-5 has ability to interact with both CYTB-5.1 and CYTB-5.2. Moreover, RNAi knockdown of cytb-5.1 upregulates the transcriptional and translational expression of fat-5 to fat-7, which may be due to the feedback induction by reduced C18:1(n-9) and downstream fatty acids. Furthermore, both CYTB-5.1 and CYTB-5.2 are involved in fat accumulation, fertility and lifespan in worms, which may be independent of changes in fatty acid compositions. Collectively, these findings for the first time reveal the differential regulation of various SCDs by distinct cytochrome b5 CYTB-5.1 and CYTB-5.2 in the biosynthesis of UFAs in C. elegans.
Volume 1863(3)
Pages 235-246
Published 2018-3-1
DOI 10.1016/j.bbalip.2017.12.007
PII S1388-1981(17)30244-5
PMID 29237573
MeSH Animals Caenorhabditis elegans / enzymology* Caenorhabditis elegans / genetics Caenorhabditis elegans Proteins / genetics Caenorhabditis elegans Proteins / metabolism* Cytochromes b5 / genetics Cytochromes b5 / metabolism* Fertility / physiology Gene Expression Regulation, Enzymologic / physiology* Longevity / physiology Stearoyl-CoA Desaturase / biosynthesis* Stearoyl-CoA Desaturase / genetics
IF 4.402
Times Cited 2
C.elegans tm331 tm420