The Four Isoforms of ST2

In addition to past research focused on inflammatory and autoimmune diseases, the role of IL-33 and the ST2 receptor are more recently being investigated in cardiovascular disease. Potential drug therapeutics for IL-33 interaction and ST2 reception are also being investigated. There are four isoforms of ST2:

1) ST2L
Also known as IL1RL1-b and previously referred to as T1M. ST2L is a transmembrane receptor very similar in structure to type I IL-1 receptors. It has an extracellular domain composed of three linked immunoglobulin-like motifs, a transmembrane segment and a TIR cytoplasmic domain. When IL-33 activates ST2L, a Th2-dependent inflammatory response is elicited causing cytokines such as IL-4 and IL-5 to be produced.  View our Human ST2L Monoclonal Antibodies or our Mouse T1/ST2 Monoclonal Antibodies.

2) sST2
Also known as IL1RL1-a and previously referred to as T1S. This form of ST2 is soluble and released into the serum upon induction. Its thought to act as an inhibitor of IL-33 and Th2 function. Structurally, sST2 lacks the transmembrane and cytoplasmic domains contained within the structure of ST2L and includes a unique nine amino-acid C-terminal sequence.  View our Mouse T1/ST2 ELISA for the quantitative determination of ST2 in mouse serum and cell culture supernate samples.

3) ST2V
ST2V is characterized by the absence of an immunoglobulin-like motif and alternative splicing of the C-terminal portion of ST2. This form is thought to be localized in the plasma membrane and is primarily found in gastrointestinal organs of human tissue.

4) ST2LV
ST2LV is created by an alternative splicing event that removes the transmembrane domain within ST2L.

Suggested review articles and links to learn more:
 - Review: The IL-33/ST2 pathway: therapeutic target and novel biomarker.  View here >
 - Review: Disease-associated functions of IL-33: the new kid in the IL-1 family.  View here >
 - GeneCards: IL1RL1 Gene >