Lymphocyte-Specific Protein Tyrosine Kinase: LCK

2020 ◽  
pp. 438-441
Author(s):  
Robert P. Nelson
Keyword(s):  
Tyrosine Kinase ◽  
Protein Tyrosine Kinase ◽  
Specific Protein ◽  
Protein Tyrosine

scholarly journals Lymphocyte-Specific Protein Tyrosine Kinase (LCK) is Involved in the Aryl Hydrocarbon Receptor-Mediated Impairment of Immunoglobulin Secretion in Human Primary B Cells

2018 ◽  
Vol 165 (2) ◽  
pp. 322-334
Author(s):  
Jiajun Zhou ◽  
Qiang Zhang ◽  
Joseph E Henriquez ◽  
Robert B Crawford ◽  
Norbert E Kaminski
Keyword(s):  
B Cells ◽  
Tyrosine Kinase ◽  
Aryl Hydrocarbon Receptor ◽  
Protein Tyrosine Kinase ◽  
Specific Protein ◽  
Immunoglobulin M ◽  
Protein Tyrosine ◽  
Immunoglobulin Secretion ◽  
Aryl Hydrocarbon

AbstractThe aryl hydrocarbon receptor (AHR) is a cytosolic ligand-activated transcription factor involved in xenobiotic sensing, cell cycle regulation, and cell development. In humans, the activation of AHR by 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), a high affinity AHR-ligand, impairs the secretion of immunoglobulin M (IgM) to suppress humoral immunity. However, the mechanisms bridging the activation of AHR and the impairment of IgM secretion by human primary B cells remain poorly understood. Recent transcriptomic analysis revealed upregulation of lymphocyte-specific protein tyrosine kinase (LCK) in AHR-activated human primary B cells. LCK is a well-characterized tyrosine kinase that phosphorylates critical signaling proteins involved in activation and cytokine production in T cells. Conversely, the role of LCK in human primary B cells is not well understood. In the current studies, we have verified the transcriptomic finding by detecting AHR-mediated upregulation of LCK protein in human primary B cells. We also confirmed the role of AHR in the upregulation of LCK by using a specific AHR antagonist, which abolished the AHR-mediated increase of LCK. Furthermore, we have confirmed the role of LCK in the AHR-mediated suppression of IgM by using LCK specific inhibitors, which restored the IgM secretion by human B cells in the presence of TCDD. Collectively, the current studies demonstrate a novel role of LCK in IgM response and provide new insights into the mechanism for AHR-mediated impairment of immunoglobulin secretion by human primary B cells.

scholarly journals SRC family kinases in hamster spermatozoa: evidence for the presence of LCK

Reproduction ◽  
2017 ◽  
Vol 153 (5) ◽  
pp. 655-669 ◽  
Author(s):  
Durgesh Kumar Singh ◽  
Rohit Kumar Deshmukh ◽  
Praveen Kumar Narayanan ◽  
Sisinthy Shivaji ◽  
Archana Bharadwaj Siva
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Protein Tyrosine Kinase ◽  
Specific Inhibitor ◽  
Specific Protein ◽  
Src Family Kinases ◽  
Sperm Capacitation ◽  
Protein Tyrosine

Sperm capacitation is a prerequisite for successful fertilization. Increase in tyrosine phosphorylation is considered the hallmark of capacitation and attempts to understand its regulation are ongoing. In this regard, we attempted to study the role of SRC family kinases (SFKs) in the hamster sperm functions. Interestingly, we found the presence of the lymphocyte-specific protein tyrosine kinase, LCK, in mammalian spermatozoa and further characterized it in terms of its localization and function. LCK was found in spermatozoa of several species, and its transcript was identified in the hamster testis. Autophosphorylation of LCK at the Y394 residue increased as capacitation progressed, indicating an upregulation of LCK activity during capacitation. Inhibition of LCK (and perhaps the other SFKs) with the use of a specific inhibitor showed a significant decrease in protein tyrosine phosphorylation of several proteins, implying LCK/SFKs as key tyrosine kinase(s) regulating tyrosine phosphorylation during hamster sperm capacitation. Dihydrolipoamide dehydrogenase was identified as a substrate for LCK/SFK. LCK/SFKs inhibition significantly reduced the percentage fertilization (in vitro) but had no effect on sperm motility, hyperactivation and acrosome reaction. In summary, this is the first report on the presence of LCK, an SFK of hematopoietic lineage in spermatozoa besides being the first study on the role of SFKs in the spermatozoa of Syrian hamsters.

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