intracellular

Examples of intracellular in the following topics:

• Types of Receptors

  • Receptors, either intracellular or cell-surface, bind to specific ligands, which activate numerous cellular processes.
  • Enzyme-linked receptors are cell-surface receptors with intracellular domains that are associated with an enzyme.
  • In some cases, the intracellular domain of the receptor itself is an enzyme or the enzyme-linked receptor has an intracellular domain that interacts directly with an enzyme.
  • Hydrophobic signaling molecules typically diffuse across the plasma membrane and interact with intracellular receptors in the cytoplasm.
  • Many intracellular receptors are transcription factors that interact with DNA in the nucleus and regulate gene expression.

• Intracellular Hormone Receptors

  • They then adhere to intracellular receptors residing in the cytoplasm or in the nucleus.
  • An intracellular nuclear receptor (NR) is located in the cytoplasm bound to a heat shock protein (HSP).
  • Describe how hormones alter cellular activity by binding to intracellular receptors

• Binding Initiates a Signaling Pathway

  • Ligand binding to cell-surface receptors activates the receptor's intracellular components setting off a signaling pathway or cascade.
  • This type of receptor spans the plasma membrane and performs signal transduction in which an extracellular signal is converted into an intracellular signal.
  • Enzyme-linked receptors are cell-surface receptors with intracellular domains that are associated with an enzyme.
  • In some cases, the intracellular domain of the receptor itself is an enzyme.
  • Other enzyme-linked receptors have a small intracellular domain that interacts directly with an enzyme.

• Invertebrate Digestive Systems

  • Invertebrates can be classified as those that use intracellular digestion and those with extracellular digestion.
  • The simplest example of digestion intracellular digestion, which takes place in a gastrovascular cavity with only one opening.
  • The food particles are engulfed by the cells lining the gastrovascular cavity and the molecular are broken down within the cytoplasm of the cells (intracellular).
  • Their food is broken down in their digestive tract (extracellular digestion), rather than inside their individual cells (intracellular digestion).

• Plasma Membrane Hormone Receptors

  • Hormones that cannot diffuse through the plasma membrane instead bind to receptors on the cell surface, triggering intracellular events.
  • Binding of these hormones to a cell surface receptor results in activation of a signaling pathway; this triggers intracellular activity to carry out the specific effects associated with the hormone.
  • In this way, nothing passes through the cell membrane; the hormone that binds at the surface remains at the surface of the cell while the intracellular product remains inside the cell.

• Components of Plasma Membranes

  • These proteins can be receptors, which work as receivers of extracellular inputs and as activators of intracellular processes, or markers, which allow cells to recognize each other.
  • Membrane receptors provide extracellular attachment sites for effectors like hormones and growth factors, which then trigger intracellular responses.

• Methods of Intracellular Signaling

  • When signaling occurs, ligand-gated calcium ion channels allow the higher levels of Ca2+ that are present outside the cell (or in intracellular storage compartments) to flow into the cytoplasm, which raises the concentration of cytoplasmic Ca2+.

• Prokaryotic versus Eukaryotic Gene Expression

  • Eukaryotic cells, in contrast, have intracellular organelles that add to their complexity.

• Forms of Signaling

  • Removing the signals will reestablish the concentration gradient for the signal, allowing them to quickly diffuse through the intracellular space if released again.
  • These water-filled channels allow small signaling molecules, called intracellular mediators, to diffuse between the two cells.

• Cell-Mediated Immunity

  • TC cells attempt to identify and destroy infected cells by triggering apoptosis (programmed cell death) before the pathogen can replicate and escape, thereby halting the progression of intracellular infections.
  • MHC I complexes display a current readout of intracellular proteins inside a cell and will present pathogen antigens if the pathogen is present in the cell.