Receptor for thymic stromal lymphopoietin (TSLP). Forms a functional complex with TSLP and IL7R which is capable of stimulating cell proliferation through activation of STAT3 and STAT5. Also activates JAK2. Implicated in the development of the hematopoietic system. The TSLP receptor is a heterodimer of CRLF2 and IL7R. Binding of TSLP to CRLF2/TSLPR is a mechanistic prerequisite for recruitment of IL7R to the high-affinity ternary complex. Additional isoforms seem to exist. High level of expression in liver, lung and testis. Also expressed in heart, brain, spleen, thymus and bone marrow. Highly expressed in progenitors and myeloid cells. Isoform 2 is expressed in primary hemotopoietic cells. Up-regulated in the myeloid 32D cell line by granulocyte colony-stimulating factor (G-CSF). The WSXWS motif appears to be necessary for proper protein folding and thereby efficient intracellular transport and cell-surface receptor binding. The box 1 motif is required for JAK interaction and/or activation. Belongs to the type I cytokine receptor family. Type 5 subfamily.