| Modification Notes |
Adaptor proteins mediate the recruitment of positive or negative regulators into signaling networks, modulate effector function by allosteric regulation of enzymatic activity, and target other proteins for degradation in response to receptor ligation (1,2). Adaptor proteins can associate with numerous molecules and are required for coupling receptor ligation with more distal signaling events in immature thymocytes, mature T cells, platelets, and mast cells (2). The SLP-76 family of adaptor proteins are expressed exclusively in cytokine-stimulated hematopoietic cells (3). The SLP-76 family member Clnk, also designated MIST (mast cell immunoreceptor signal transducer) is structurally related to SLP-76 and BLNK/BASH/SLP-65 hematopoietic cell-specific adaptor proteins (4,5). The human Clnk gene maps to chromosome 4 and encodes a 376 amino acid protein (6). In activated T cells and myeloid cells, the serine/threonine-specific protein kinase HPK-1 can be recruited to macromolecular complexes through Clnk and cause immunoreceptor-mediated activation of the interleukin 2 (IL-2) promoter (3). |