Related Experiment Video

Updated: Aug 18, 2026

Measuring Intracellular Ca2+ Changes in Human Sperm using Four Techniques: Conventional Fluorometry, Stopped Flow Fluorometry, Flow Cytometry and Single Cell Imaging
19:26

Measuring Intracellular Ca2+ Changes in Human Sperm using Four Techniques: Conventional Fluorometry, Stopped Flow Fluorometry, Flow Cytometry and Single Cell Imaging

Published on: May 24, 2013

Calmodulin level and cAMP-dependent protein kinase activity in rat spermatogenic cells and hormonal control of

J Feinberg, C Pariset, S Weinman

    Developmental Biology
    |March 1, 1985
    PubMed

    More Related Videos

    Phosphopeptide Analysis of Rodent Epididymal Spermatozoa09:30

    Phosphopeptide Analysis of Rodent Epididymal Spermatozoa

    Published on: December 30, 2014

    Recording Electrical Currents across the Plasma Membrane of Mammalian Sperm Cells09:37

    Recording Electrical Currents across the Plasma Membrane of Mammalian Sperm Cells

    Published on: February 14, 2021

    Related Concept Videos

    Spermatogenesis01:41

    Spermatogenesis

    Spermatogenesis is the process by which haploid sperm cells are produced in the male testes. It starts with stem cells located close to the outer rim of seminiferous tubules. These spermatogonial stem cells divide asymmetrically to give rise to additional stem cells (meaning that these structures “self-renew”), as well as sperm progenitors, called spermatocytes. Importantly, this method of asymmetric mitotic division maintains a population of spermatogonial stem cells in the male reproductive...
    Positive Regulator Molecules02:39

    Positive Regulator Molecules

    Mitotic cell division results in daughter cells that exactly resemble the parent cell. However, errors in the DNA replication or distribution of genetic material may lead to genetic mutations that may be passed down to every new cell formed from the resulting abnormal cell. Propagation of such mutant cells is restricted through checkpoint mechanisms present at different stages of the cell cycle. These checkpoints involve regulator molecules that either promote or demote cell cycle events.
    Amplifying Signals via Second Messengers01:15

    Amplifying Signals via Second Messengers

    Many receptor binding ligands are hydrophilic; they do not cross the cell membrane but bind to cell-surface receptors. Thus, their message must be relayed by second messengers present in the cell cytoplasm. There are several second messenger pathways, each with its own way of relaying information. For example, the G protein-coupled receptors can activate both phosphoinositol and cyclic AMP (cAMP) second messenger pathways. The phosphoinositol pathway is active when the receptor induces...
    cAMP-dependent Protein Kinase Pathways01:25

    cAMP-dependent Protein Kinase Pathways

    Cyclic Adenosine Monophosphate (cAMP) is an essential second messenger that activates protein kinase A (PKA) and regulates various biological processes. A single epinephrine molecule binds to GPCR and activates several heterotrimeric G proteins, each stimulating multiple adenylyl cyclase, amplifying the signal, and synthesizing large numbers of cAMP molecules. Small changes in cAMP concentration affect PKA activity. The binding of four cAMP molecules induces a conformational change in PKA,...
    Feedback Regulation of Calcium Concentration01:27

    Feedback Regulation of Calcium Concentration

    Calcium is an essential signaling molecule required for various cellular functions. Calcium pumps and ion channels on cell and organellar membranes, such as those on the endoplasmic reticulum (ER), regulate calcium concentrations inside the cell. They remain closed, keeping the cytosolic calcium levels low at a resting state.
    Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
    Calmodulin-dependent Signaling01:16

    Calmodulin-dependent Signaling

    Calmodulin (CaM) is a calcium-binding protein in eukaryotes that controls various calcium-regulated cellular processes. It has four calcium-binding sites that bind calcium to form the calcium-calmodulin ( Ca2+-CaM) complex. GPCR stimulation increases the calcium levels in the cells that bind to CaM and induces a conformational change.
    The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...