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

Abstract

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 () 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.

Src family kinases-mediated negative regulation of sperm acrosome reaction in chickens (Gallus gallus domesticus)

“…p-SFK-Y416 was present in patch-like patterns over the sperm head, including the acrosomal region, which differed from the c-Src only enriched in the sperm head except for acrosomal region. This suggests that the primary SFK being phosphorylated is not c-Src, which is consistent with previous results showing a species-specific preference of phosphorylated SFK members in mammalian sperm [24]. Further research is required to identify the SFKs in chicken sperm.…”

“…The presence of SFKs have been reported in the sperm of a few species [24,25]. Our immunoblotting analysis showed the presence of c-Src, a prototypic member of SFK, in addition to p-SFK-Y416, in chicken sperm.…”

“…SFKs are a representative group of non-receptor tyrosine kinases (c-Src, Yes, Fyn, Fgr, Lck, Hck, Blk, and Lyn), and they contribute to cell adhesion and migration [22]. In sperm, the nature of their expression and activation in response to tyrosine 416 phosphorylation differs among subtypes or species [23][24][25], suggesting the presence of a redundant mechanism for AR regulation. Although the regulatory mechanism for SFK activity in sperm is not understood because of these different natures, studies on immune cells [26] and discoveries related to human sperm [27] suggest that some SFK subtypes are functionally regulated by membrane rafts (MRs).…”

Target Identification of Active Constituents of Shen Qi Wan to Treat Kidney Yang Deficiency Using Computational Target Fishing and Network Pharmacology

“…Tubular epithelial cells (TECs) play an important role in renal diseases, especially in tubulointerstitial inflammation and fibrosis, which is a pathological process involved in a variety of cytokines and inflammatory mediators. Lymphocyte-specific protein-tyrosine kinase ( LCK ) and a SRC family protein-tyrosine kinase are located in the cytoplasm of TECs and form the key signal transduction molecule in the process of intracellular signal transduction (Singh et al, 2017). Li et al have investigated the effect of the LCK pathway activation on the IL-12 signal transduction of TECs and found that LCK may regulate the LCK c-Jun signaling pathways in TEC, while the inflammation of TEC mediated by the activation of the LCK pathway is related to the expression of c-Jun promoted by IL-12 (Li et al, 2001).…”