Our work aims at the multifactorial study of cellular physiological parameters that help to interpret and understand intracellular signaling pathways from the point of view of systemic biology. To reach this goal, we use different tools that allow the reading of multiple intracellular factors. Our group uses mouse spermatozoa as the main cell model. Being spermatozoa transcriptional and translationally inactive, it is presented as an exceptional model for the study of intracellular signaling mechanisms based on post-translational modification. In addition, the studies derived from the basic research in mouse sperm allow the extrapolation tu human sperm and other mammalian models, with implications in the reproductive clinic, and on the other hand, to commercially interesting species. In mammals, spermatozoa lack fertilizing capacity at the time of ejaculation. These cells acquire the “capacitated” state within the reproductive female tract. However, sperm capacitation can be accomplished in the laboratory by incubating spermatozoa for as little as one hour (for mouse sperm) in defined culture media. Current knowledge indicates that the functional changes that lead to capacitation respond to a combination of both simultaneous and sequential processes. Some of these processes occur as soon as the sperm are released from the epididymis, while other changes occur more slowly being fired only after a certain period of time. At the biological level, sperm capacitation is associated with both a change in the mode of flagellar beating called hyperactivation and the ability of the sperm to trigger the process called acrosomal exocytosis upon contact with a physiological agonist. Protein Kinase PKA (PKA) plays a key role in both the rapid and slow events associated with capacitation. These events include: 1) hyperpolarization of the sperm plasma membrane; 2) A cytoplasmic increase of the Ca2+ concentration; 3) Activation of Tyr kinases; 4) Both inactivation and activation of different Thr/Ser phosphatases; 5) Modification of the lipid constitution of the plasma membrane; 6) Actin polymerization. With these events in mind, it is clear that sperm represent an excellent model for the study of signaling cascades, considering the processes that are triggered within one hour, together with the ease of obtaining the samples. Our laboratory is currently focused on understanding the mechanisms by which PKA activity is regulated during capacitation, specifically related to hyperpolarization of the plasma membrane. This hyperpolarization, as in other cell types, is key to enabling subsequent processes, such as acrosomal exocytosis in the sperm. The mechanisms by which PKA promotes hyperpolarization are not fully understood. Added to this, the question that still persists is how, after immediate activation of PKA in capacitation medium  (coincident with the increase of cAMP derived from sAC), hyperpolarization takes longer times to achieve This question is extensive to a series of events that, being commanded by PKA, take longer to occur, such as actin polymerization and the activation of Tyr kinases as Src. Our group identified that PKA promotes the activation of Src, then allowing its full activation by Src-Tyr416 phosphorylation. In turn, by heterologous expression of Slo3 in Xenopus oocytes, we saw that Src is fundamental for the sensitization of the potassium BK channel Slo3, responsible for the hyperpolarization of Em. Results derived from these studies help to understand the regulation of these events in different cell types, for example in the regulation of Src in different types of cancer. Our objective is to understand the regulation of various signaling cascades, that while triggered by same mechanisms, are controlled both temporally and spatially in a dissimilar way in cellular systems. Our group, made up of a network of collaborators, integrates different techniques, combining the analysis of physiological parameters derived from single cell studies such as flow cytometry and super-resolution microscopy, with population measurements such as cell fluorimetry and mass spectrometry .