Introduction: Cell signaling and signal transduction 1. Cell Signaling (1) Direct Intercellular Communication Gap Junction magnet ◆ Gap Junction (2)Signaling by plasma-membrane bound molecules (3) Receptor-Mediated Intercellular communication Cell-Surface Receptors ◆ Nuclear Receptors SIGNALING BY PLASMA-MEMBRANE-BOUND MOLECULES SIGNALING BY SECRETED MOLECULES SIGNALING TARGET SIGNALING TARGET CELL CELL CELL CELI signaling molecu鲁 receptor moleculeIntroduction: Cell signaling and Signal transduction 1. Cell Signaling (1) Direct Intercellular Communication ◆Gap Junction (2) Signaling by plasma-membrane bound molecules (3) Receptor-Mediated Intercellular communication ◆Cell-Surface Receptors ◆Nuclear Receptors Gap Junction