sentences:  Type I IFNs have a binding association rate of 10−6–10−7M/s with a variable dissociation rate that determines type I IFN subtype affinity for IFNAR2.IFNAR2 is expressed as three isoforms due to alternative splicing, exon skipping, and multiple polyadenylation sites; IFNAR2a (a soluble form lacking the TM domain), IFNAR2b (a soluble form lacking the cytoplasmic domain), and IFNAR2c (the membrane bound, signaling-competent form).The cytoplasmic domain of IFNAR2c associates with JAK1.