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Phosphorylation of the adaptor protein PSTPIP2 and its role in neutrophilic granulocytes
Dvořáček, Tomáš ; Brdička, Tomáš (advisor) ; Ballek, Ondřej (referee)
PSTPIP2 is an adaptor protein of the F-BAR family, which is an important regulator controlling the effector mechanisms of innate immune cells. The regulatory functions of this protein were discovered thanks to the CMO mouse strain, which lost the expression of this protein. As a result of PSTPIP2 deficiency, mice of the CMO strain develop an autoinflammatory disease affecting bone tissue and skin. The main mechanism that drives its pathology is the loss of regulation of the neutrophil granulocyte activity. These cells then produce excessive amounts of the pro-inflammatory cytokine IL-1β and reactive oxygen species. However, the exact molecular mechanism of action of the PSTPIP2 protein is unknown. When the PSTPIP2 protein is activated, it is phosphorylated and interacts with other proteins, which mediate its regulatory function. Interaction partners described so far in neutrophil granulocytes include phosphatases of the PEST family, the lipid phosphatase SHIP1 and the non-receptor tyrosine kinase CSK. In this thesis, we identified kinases from the SRC family as kinases that phosphorylate PSTPIP2. Furthermore, we found that the main phosphorylation sites of PSTPIP2 are tyrosines at positions 323 and 329. Finally, we proved that SHIP1 can bind to the phosphotyrosine motif around the tyrosine at...
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New leukocyte membrane adaptor proteins
Králová, Jarmila ; Brdička, Tomáš (advisor) ; Černý, Jan (referee) ; Šedivá, Anna (referee)
Membrane adaptor proteins are characterized by the lack of enzymatic activity and the presence of various interaction sites for other proteins and cellular membranes. They typically function as scaffolds connecting receptors or other adaptors with proximal signaling molecules at cellular membranes. Their overall effects on signaling can be activating or inhibiting depending on the nature of the effector molecules they recruit. SCIMP is one of the membrane adaptors discussed in this thesis. It is expressed in antigen- presenting cells and it has been previously shown to enhance MHCII signaling in B cells. This thesis covers the analysis of SCIMP functions beyond B cells and describes the first analysis of SCIMP deficient mice. Although the results of this analysis did not show any alterations in immune cell populations, the novel function of SCIMP in dendritic cell signaling downstream of DECTIN- 1 was uncovered. DECTIN-1 is a pattern recognition receptor involved in antifungal immunity. The data presented in this thesis describe the role of SCIMP in sustaining DECTIN-1 signaling over relatively long periods of time and the contribution of SCIMP signaling to maintaining prolonged production of pro-inflammatory cytokines. PSTPIP2 is another interesting adaptor discussed in this thesis. It is...
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The role of protein tyrosine phosphatase CD45 and Src-family kinases in murine model of chronic autoinflammatory osteomyelitis
Ilievová, Kristýna ; Brdička, Tomáš (advisor) ; Černý, Jan (referee)
The development of autoinflammatory diseases is caused by the dysregulation of innate immune mechanisms. This leads to the development of spontaneous inflammation. Mice lacking adaptor protein PSTPIP2 develop chronic autoinflammatory osteomyelitis due to higher activity of neutrophil granulocytes and their increased production of IL-1β. .β. PSTPIP2 interacts with PEST phosphatases and kinase CSK. These proteins are impor- tant negative regulators of Src family kinases. In this diploma thesis, the role of Src family kinases and the role of their positive regulator phosphatase CD45 in the development of chronic autoinflammatory osteomyelitis was studied. For this purpose, a mouse model of chronic autoinflammatory osteomyelitis (CMO) lacking CD45 was used. These mice deve- lop the disease with delayed kinetics. Bone marrow cells isolated from these mice produce less IL-1β. upon silica activation and have lower phosphorylation of ERK MAP kinase. It isβ. probably caused by higher phosphorylation of the inhibitory tyrosine of Src family kinases resulting in their lower activity. The presence of different immune cell populations in the bone marrow, spleen and blood of these mice was also monitored in these mice. The re- sults of this work contribute to a better understanding of the role of Src family...
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New leukocyte membrane adaptor proteins
Králová, Jarmila ; Brdička, Tomáš (advisor) ; Černý, Jan (referee) ; Šedivá, Anna (referee)
Membrane adaptor proteins are characterized by the lack of enzymatic activity and the presence of various interaction sites for other proteins and cellular membranes. They typically function as scaffolds connecting receptors or other adaptors with proximal signaling molecules at cellular membranes. Their overall effects on signaling can be activating or inhibiting depending on the nature of the effector molecules they recruit. SCIMP is one of the membrane adaptors discussed in this thesis. It is expressed in antigen- presenting cells and it has been previously shown to enhance MHCII signaling in B cells. This thesis covers the analysis of SCIMP functions beyond B cells and describes the first analysis of SCIMP deficient mice. Although the results of this analysis did not show any alterations in immune cell populations, the novel function of SCIMP in dendritic cell signaling downstream of DECTIN- 1 was uncovered. DECTIN-1 is a pattern recognition receptor involved in antifungal immunity. The data presented in this thesis describe the role of SCIMP in sustaining DECTIN-1 signaling over relatively long periods of time and the contribution of SCIMP signaling to maintaining prolonged production of pro-inflammatory cytokines. PSTPIP2 is another interesting adaptor discussed in this thesis. It is...
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