Development and Signaling Mechanisms Quiz

Development and Signaling Mechanisms

• Ligand binding causes a receptor to undergo a conformational change and autophosphorylation, becoming an active tyrosine kinase.
• Ligands can be hormones or paracrine factors serving as inductive signals affecting nearby cells.
• Paracrine factors are diffusible molecules produced by inducing cells that influence adjacent cells, leveraging positional signaling (para = "side").
• The extracellular matrix (ECM) comprises components such as laminins, fibronectins, integrins, and cell adhesion molecules (CAMs) that facilitate cell attachment and signaling.
• Components of the ECM are produced by inducing cells, which subsequently influence nearby cells' behavior.

Distinction of Juxtacrine Signaling

• Juxtacrine signaling differs from paracrine signaling in that it involves direct cell-to-cell communication rather than diffusible signals.
• Phospholipase C plays a role by cleaving phospholipid molecules, impacting cellular responses.

Summary of Ligand-Receptor Interaction

• Ligand-Receptor (L-R) binding initiates a cascade that regulates transcription factors and cofactors at the nuclear level, triggering gene expression programs.
• New gene expression ultimately leads to cellular changes in embryonic cells.
• Inductive signals, ligands, and membranes involve various mechanisms to promote transduction and translation of the signals within cells, facilitating subsequent cellular responses.

Components of the Induction-Response System

• Signals include inductive signals and ligands, which interact with receptors located on the responding cell membrane.
• Mechanisms transport the signal and translate it, stimulating cellular responses through intermediates or activated products in signaling pathways.

Receptor Tyrosine Kinase (RTK)

• RTKs are integral players in signaling cascades and serve as pivotal enzymes for phosphorylation of proteins.
• They regulate various pathways impacting cellular growth and differentiation by phosphorylating downstream targets.

Secondary Induction Mediators

• Secondary induction relies on paracrine signaling factors and growth/differentiation factors, including:
  • Fibroblast Growth Factors (FgFs)
  • Hedgehog family factors
  • Wingless family (Wnt)
  • Transforming Growth Factors Beta Superfamily
• Juxtacrine signaling mechanisms involve Delta-Notch interactions, where Delta acts as the ligand and Notch serves as the receptor to propagate intracellular signals. Other binding ligands include Serrate and Jagged.