Communication signal pathways Distinguish among types of celltocell

Communication- signal pathways • Distinguish among types of cell-to-cell communication • List the four classes of membrane receptors. • Explain how receptors facilitate specific cellular responses • List and describe the components in specific 2 nd messenger signal transduction pathways (see tables 6. 1 and 6. 2)

Autocrine Paracrine

Neurotransmitter Hormone

blood vessel connective tissue muscle epithelium The muscle around a blood vessel contracts & relaxes This is regulated by: autocrines, paracrines (H+, CO 2, etc) endocrines (ADH, ANP) neurotransmitters (NE, E)

Four classes of membrane receptors: There also intracellular (non-membrane-bound) receptors that typically act as transcription regulators.

tyrosine kinase receptor/enzyme

G-protein coupled receptor G

Two main classes of 7 Trans-membrane domain, G-protein coupled receptors (GPCR) 1. GPCRs that modulate adenylate cyclase, which converts ATP to c. AMP, which activates protein kinase A. 2. GPCRs that activate PLC leading to hydrolysis of polyphosphoinositides (e. g. PIP 2) generating the second messengers, diacylglycerol (DAG) & inositoltrisphosphate (IP 3). DAG activates protein kinase C. IP 3 releases intracellular calcium stores.

http: //www. blackwellpublishing. com/matthews/neurotrans. html http: //entochem. tamu. edu/Teaching/G-Protein/GProteinaudio. Movie. html