While molecular glues are mostly designed and synthesized in the lab, there are also some natural compounds that were found to function as molecular glues. Cyclosporin A (CsA, Table ) is binding partner of cyclophilin 18 (Cyp18)-CsA complex. The Cyp18-CsA complex recruits calcium/calmodulin dependent serine-threonine protein phosphatase calcineurin (CN) resulting in blocking the transcription of cytokine genes in activated T cells. CsA is a highly specific inhibitor of T cell activation. Voclosporin (Lupkynis, Table ) was approved by the U.S. FDA to treat adults with lupus nephritis. Voclosporin is a novel immunomodulatory drug inhibiting the calcineurin enzyme with the same mechanism of action as CsA. Sanglifehrin A (SfA, Table ) has antiproliferative and immunosuppressive activity through inhibiting both T-cell and B-cell proliferation. SfA is a binding partner for the SfA-Cyp18 complex and inosine-5'-monophosphate dehydrogenase 2 (IMPDH2). The ternary complex formation modulates cell growth through interaction with the cystathionine-β-synthase (CBS) domain of IMPDH2. Plant hormones Auxin (AUX, indole-3-acetic acid, IAA, Table ) and Jasmonate (JA, Table ) are simply structured natural molecular glues. Auxin binds directly to the Skp1-cullin 1-F-box (SCF) E3 ubiquitin protein ligase TIR1 and attracts AUX proteins for degradation. Jasmonate also utilizes the E3 ubiquitin ligase SCF TIR1 to attract and degrade Jasmonate-ZIM (JAZ) domain proteins. AUX/IAA and JAZ represent families of transcriptional repressors, which upon degradation lead to the expression of Auxin-and JAinducible genes.