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SPOTS complex Overview

GO Annotations consist of four mandatory components: a gene product, a term from one of the three Gene Ontology (GO) controlled vocabularies (Molecular Function, Biological Process, and Cellular Component), a reference, and an evidence code.

Summary
Serine C-palmitoyltransferase (SPT) catalyzes the first committed step in the biosynthesis of sphingolipids: condensation of serine with palmitoyl-CoA to form 3-ketosphinganine. The catalytic activity depends on LCB1 and LCB2, and is stimulated several-fold by TSC3. The remaining components are believed to play regulatory roles. Mature sphingolipids are an essential component of the plasma membrane. Moreover, several intermediates in sphingolipid metabolism are important signaling molecules involved in control of growth and stress response. Tight regulation of this rate-limiting step in sphingolipid synthesis is therefore critical for lipid homeostasis, membrane biogenesis, protein quality control and trafficking through the secretory pathway. Regulation of sphingolipid synthesis is mediated by phosphorylation of ORM1 and ORM2 as well as by up-regulation of ORM2 protein levels. Sphingolipid depletion activates the TORC2 complex (CPX-1717), which triggers ORM1 and ORM2 phosphorylation by the protein kinase YPK1 (P12688). Inhibition of the nutrient-sensitive TORC1 complex (CPX-1715 /CPX-1716) triggers phosphorylation of ORM proteins by the protein kinase NPR1 (P22211). Increased phosphorylation of ORM proteins reduces their inhibitory activity resulting in stimulation of SPOTS and increased sphingolipid synthesis. In addition, the presence of the phosphoinositide phosphatase SAC1 (P32368) in the SPOTS complex appears to link sphingolipid synthesis to phosphoinositide signaling that controls ER functions and ER-to-Golgi traffic. Thus, the SPOTS complex may be responsible for coordinating sphingolipid homeostasis with a variety of processes that control cell growth and response to nutrients.
GO Slim Terms

The yeast GO Slim terms are higher level terms that best represent the major S. cerevisiae biological processes, functions, and cellular components. The GO Slim terms listed here are the broader parent terms for the specific terms to which this gene product is annotated, and thus represent the more general processes, functions, and components in which it is involved.

acyltransferase activity, transferase activity, homeostatic process

Biological Process

Manually curated GO annotations reflect our best understanding of the basic biological process for this protein complex. Manually curated annotations are assigned by curators based on published papers when available, or by curatorial statements if necessary. Curators periodically review all manually curated GO annotations for accuracy and completeness.

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Qualifier Gene Ontology Term Annotation Extension Evidence Source Assigned On Reference

Molecular Function

Manually curated GO annotations reflect our best understanding of the basic molecular function for this protein complex. Manually curated annotations are assigned by curators based on published papers when available, or by curatorial statements if necessary. Curators periodically review all manually curated GO annotations for accuracy and completeness.

Increase the total number of rows showing on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table.

Qualifier Gene Ontology Term Annotation Extension Evidence Source Assigned On Reference

Shared Annotations

This diagram displays Gene Ontology terms (green) that are shared between the given macromolecular complex (black) and other yeast complexes (yellow). Note: No diagram is shown ("No shared annotations") if there are less than 2 shared GO annotations between this complex and any other complexes.