Activating Compound | Comment | Organism | Structure |
---|---|---|---|
small subunits of serine palmitoyltransferase | isoforms ssSPTa and ssSPTb, UniProt A8MSB8 and F4IPU5, strongly stimulate SPT activity. Small subunit ssSPTa transcripts are more enriched in all organs and over 400fold more abundant in pollen than small subunit ssSPTb transcripts. Homozygous ssSPTa T-DNA mutants are not recoverable, and 50% nonviable pollen is detected in heterozygous ssspta mutants. The small subunits are essential for male gametophytes, are important for mycotoxin fumonisin B1 sensitivity, and limit sphingolipid synthesis in planta | Arabidopsis thaliana |
Cloned (Comment) | Organism |
---|---|
recombinant expression of FLAG-tagged enzyme subunit LCB1 and of Myc-tagged enzyme subunit LCB2 in Saccharomyces cerevisiae microsomes. Expressing the Arabidopsis thaliana LCB1/LCB2 heterodimers has very low SPT activity, whereas coexpression of Arabidopsis thaliana ssSPTs, ssSPTa and ssSPTb, derived 56-amino acid polypeptides in a Saccharomyces cerevisiae enzyme SPT null mutant and stimulate SPT enzyme activity of the Arabidopsis LCB1/LCB2 heterodimer by over 100fold through physical interaction with LCB1/LCB2. Transient Agrobacterium tumefaciens-mediated transformation of Nicotiana benthaminana with YFP-labeled small subunits of serine palmitoyltransferase, ssSPTa and ssSPTb | Arabidopsis thaliana |
Protein Variants | Comment | Organism |
---|---|---|
additional information | T-DNA disruption of ssSPTa results in loss of pollen viability | Arabidopsis thaliana |
Inhibitors | Comment | Organism | Structure |
---|---|---|---|
mycotoxin fumonisin B1 | enzyme sensitivity to the inhibitor is increased by small subunit ssSPTa overexpression | Arabidopsis thaliana |
Localization | Comment | Organism | GeneOntology No. | Textmining |
---|---|---|---|---|
microsome | - |
Arabidopsis thaliana | - |
- |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Arabidopsis thaliana | - |
- |
- |
Source Tissue | Comment | Organism | Textmining |
---|---|---|---|
pollen | small subunit ssSPTa transcripts are more enriched in all organs and over 400fold more abundant in pollen than small subunit ssSPTb transcripts | Arabidopsis thaliana | - |
Subunits | Comment | Organism |
---|---|---|
heterodimer | serine palmitoyltransferase is composed of LCB1 and LCB2 subunits | Arabidopsis thaliana |
Synonyms | Comment | Organism |
---|---|---|
serine palmitoyltransferase | - |
Arabidopsis thaliana |
SPT | - |
Arabidopsis thaliana |
General Information | Comment | Organism |
---|---|---|
malfunction | homozygous ssSPTa T-DNA mutants are not recoverable, and 50% nonviable pollen is detected in heterozygous ssSpta mutants. Pollen viability is recovered by expression of wild-type ssSPTa or ssSPTb under control of the ssSPTa promoter, indicating ssSPTa and ssSPTb functional redundancy. SPT activity and sensitivity to the PCD-inducing mycotoxin fumonisin B1 are increased by ssSPTa overexpression. Conversely, SPT activity and mycotoxin fumonisin B1 sensitivity are reduced in ssSPTa RNA interference lines | Arabidopsis thaliana |
metabolism | serine palmitoyltransferase, composed of LCB1 and LCB2 subunits, catalyzes the primary regulatory point for sphingolipid synthesis | Arabidopsis thaliana |
physiological function | enzyme activators, the small subunits are essential for male gametophytes, are important for mycotoxin fumonisin B1 sensitivity, and limit sphingolipid synthesis in planta | Arabidopsis thaliana |