FADS1

The protein encoded by this gene is a member of the fatty acid desaturase (FADS) gene family. Desaturase enzymes regulate unsaturation of fatty acids through the introduction of double bonds between defined carbons of the fatty acyl chain. FADS family members are considered fusion products composed of an N-terminal cytochrome b5-like domain and a C-terminal multiple membrane-spanning desaturase portion, both of which are characterized by conserved histidine motifs. This gene is clustered with family members FADS1 and FADS2 at 11q12-q13.1; this cluster is thought to have arisen evolutionarily from gene duplication based on its similar exon/intron organization. [provided by RefSeq]

fatty acid desaturase 1

Isoform 1:
Acts as a front-end fatty acyl-coenzyme A (CoA) desaturase that introduces a cis double bond at carbon 5 located between a preexisting double bond and the carboxyl end of the fatty acyl chain. Involved in biosynthesis of highly unsaturated fatty acids (HUFA) from the essential polyunsaturated fatty acids (PUFA) linoleic acid (LA) (18:2n-6) and alpha-linolenic acid (ALA) (18:3n-3) precursors. Specifically, desaturates dihomo-gamma-linoleoate (DGLA) (20:3n-6) and eicosatetraenoate (ETA) (20:4n-3) to generate arachidonate (AA) (20:4n-6) and eicosapentaenoate (EPA) (20:5n-3), respectively (PubMed:10601301, PubMed:10769175).

As a rate limiting enzyme for DGLA (20:3n-6) and AA (20:4n-6)-derived eicosanoid biosynthesis, controls the metabolism of inflammatory lipids like prostaglandin E2, critical for efficient acute inflammatory response and maintenance of epithelium homeostasis. Contributes to membrane phospholipid biosynthesis by providing AA (20:4n-6) as a major acyl chain esterified into phospholipids. In particular, regulates phosphatidylinositol-4,5-bisphosphate levels, modulating inflammatory cytokine production in T-cells (By similarity).

Also desaturates (11E)-octadecenoate (trans-vaccenoate)(18:1n-9), a metabolite in the biohydrogenation pathway of LA (18:2n-6) (By similarity).

Isoform 2:
Does not exhibit any catalytic activity toward 20:3n-6, but it may enhance FADS2 activity.

Alpha-linolenic acid metabolic process Source: Reactome
Cell-cell signaling Source: UniProtKB
Cellular response to starvation Source: UniProtKB
Icosanoid biosynthetic process Source: UniProtKB
Linoleic acid metabolic process Source: Reactome
Long-chain fatty acid biosynthetic process Source: MGI
Phospholipid biosynthetic process Source: UniProtKB
Regulation of cell differentiation Source: UniProtKB
Regulation of transcription, DNA-templated Source: UniProtKB
Unsaturated fatty acid biosynthetic process Source: UniProtKB

Isoform 1: Endoplasmic reticulum membrane; Mitochondrion
Isoform 2: Endoplasmic reticulum membrane

Cytoplasmic: 1-121
Helical: 122-142
Lumenal: 143-145
Helical: 146-170
Cytoplasmic: 171-267
Helical: 268-288
Lumenal: 289-305
Helical: 306-326
Cytoplasmic: 327-444