Immunoglobulin superfamily member 9 (IGSF9)

Immunoglobulin superfamily member 9 (IGSF9) is a cell adhesion molecule belonging to the immunoglobulin superfamily, predicted to mediate cell–cell adhesion and involved in the guidance and development of neuronal axons and dendrites[1][2][3][4]. Its protein structure includes five extracellular immunoglobulin domains, two fibronectin type III domains, a transmembrane segment, and a substantial cytoplasmic tail[3]. IGSF9 is principally expressed in the nervous system, where it participates in synapse maturation, inhibitory synapse function, dendrite outgrowth, neuronal excitability, and the organization of synapses[1][2][4]. It also functions as a suppressor of tumor dissemination: in breast cancer and colorectal cancer, decreased IGSF9 expression or gene copy number loss is correlated with increased tumor invasiveness, metastasis, and poor prognosis[1][3]. IGSF9 is transcriptionally regulated by p53, interacts with focal adhesion kinase (FAK) to inhibit FAK/AKT signaling, and thereby acts as a molecular brake on migration and invasion pathways in cancer[3]. In the brain, loss of IGSF9 or its isoform IGSF9B affects inhibitory signaling and is implicated in neuropsychiatric and neurodevelopmental conditions[1]. IGSF9 does not yet have established drug ligands or approved targeted therapies, but its cell adhesion and signaling roles make it a promising candidate for future drug development, biomarker studies, or as a modulator in cancer and neurobiology[1][3][4].

Other names

Protein turtle homolog AIGSF9AKIAA1355NRT1IgSF9Aturtle homolog Aimmunoglobulin superfamily member 9AFP18798TUTLA_HUMAN

No drugs were found directly targeting this molecule; thus, no mechanisms of drug action documented