Decoding the signalling profile of hematopoietic progenitor kinase 1 (HPK1) in innate immunity: a proteomic approach

ABSTRACT: The fine-tuned spatiotemporal response of leukocytes to external stimuli is a hallmark of the immune system. Sensing of stimuli occurs through cell surface receptors, which transmit signals into the cell. Signaling via β2 integrins, B cell, and T cell receptors involve similar pathways. However, the activation of the same signaling molecule can result in opposing cell effector functions. One such example is the hematopoietic progenitor kinase 1 (HPK1), which negatively regulates activation of B and T cells but in contrast enforces neutrophil activation upon β2 integrin receptor engagement. Whether this difference is determined by specific interacting proteins might be disclosed by decoding the binding partners of HPK1. In the adaptive immune system, the interactome of HPK1 has already been described, whereas it is unknown in innate immune cells. Therefore, we set out to identify interacting proteins of HPK1 in the myeloid system. Neutrophil-like differentiated HL-60 cells were exposed to immobilized fibrinogen and either stimulated with Mn2+ to allow β2 integrin-mediated adhesion or left unstimulated for control. Co-immunoprecipitation experiments followed by mass spectrometry led to the identification of 116 proteins interacting with HPK1 in total. Here, 58 proteins were found only in unstimulated cells and 39 proteins only in Mn2+-stimulated adherent cells. From these results we constructed the interacting network of HPK1 with signaling, cytoskeleton-associated, transmembrane, adapter, and other proteins. Taken together, our study provides comprehensive insights into the HPK1 interactome in innate immune cells paving the way to a deeper understanding of the complex signaling profile of HPK1 in leukocytes.

INSTRUMENT(S): Q Exactive HF

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Neutrophil

SUBMITTER: Ignasi Forne  

LAB HEAD: Prof Dr Barbara Walzog

PROVIDER: PXD021136 | Pride | 2022-02-10

REPOSITORIES: Pride