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Cell Communication. Chapter 9. Cell Communication. Ligand Receptor Protein Cells select what signals to respond to. Signaling depends on distance. Direct Contact Paracrine Endocrine Synaptic Autocrine. Signal Transduction. The events that occur within the cell on receipt of a signal
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Cell Communication Chapter 9
Cell Communication • Ligand • Receptor Protein • Cells select what signals to respond to
Signaling depends on distance • Direct Contact • Paracrine • Endocrine • Synaptic • Autocrine
Signal Transduction • The events that occur within the cell on receipt of a signal • Differ from cell to cell • Phosphoralation and Dephosphorolation • Protein Kinases • Phosphatases
Types of Receptors Intracellular Cell Surface Membrane Receptors
Types of Membrane Receptors • Channel Linked- chemically gated • Enzymatic Receptors • G-Protein- Coupled- used second messengers such as cAMP and calcium
Intracellular Receptors • Found inside of cell • Lipid Soluble molecules use them…Like what?
Receptor Kinases • Phosphorylate proteins to alter function • Can attribute to cancer • RTK’s single transmembrane
Scaffold Proteins and RAS proteins • Organize Kinase Cascade in the cytoplasm • RAS links the RTK’s with the kinase cascades
Deactivation of RTK’s • Dephosphorylation • Internalization
G-protein coupled Receptors (CPCRs) • In its on state it activates the effector proteins to cause cellular response
Effector Proteins cause secondary messengers • cAMP- activates the enzyme protein kinase which adds phosphates to specific proteins. • If deficient can cause cholera • IP3- can also activate protein kinase • Calcium-very versatile • Different Receptors can produce the same second messenders
G-Protein Coupled Receptors and Tyrosine Kinase receptors can activate the same pathways… • Why is this beneficial?
Cell to Cell Interactions • Surface Proteins Give Cells Identity • Cell connections mediate cell to cell adhesion
Surface Proteins • Glycolipids • ABO blood types • MHC proteins
Cell Connections • Cell-Junctions- permanent connections • Tight Junctions…where found? • Anchoring Junctions • Cadherin and actin and intermediate filaments • Integrin-mediated • Adherins- connect actin to actin or to ecm- linking junctions called integrins • Communicating Junctions • Gap Junctions • Plasmodesmata