Term
| direct communication occurs through which cellular structure |
|
Definition
| gap junctions which are regulated pores that allow chemicals and electrical information to pass from cell to cell |
|
|
Term
|
Definition
| signaling molecules that have very limited range because of rapid uptake by other cells. they are released from cells in very close proximity to target...like endothelial cells that release NO |
|
|
Term
|
Definition
| signaling molecules that bind to receptors on the same cell that released them, creating a negative feedback that modulates release |
|
|
Term
| what do ligand-gated channels do |
|
Definition
| Facilitate comm between neurons and target cells |
|
|
Term
| how do ligand gated channels work |
|
Definition
| ligand binding causes conformational change that opens channel and allows ions to flow across membrane through pore |
|
|
Term
| what types of ions are typically used to create an electrical potential accross a membrane due to ligand binding channels? |
|
Definition
|
|
Term
| size of GPCR family and where are they found? |
|
Definition
| Large and diverse family of proteins that are found in both neural and nonneural tissues |
|
|
Term
|
Definition
| 7 membrane-spanning-regions that weave back and forth across memebrane |
|
|
Term
| what are GPCRs tranduced by |
|
Definition
| receptor binding is transduced by a G protein which has the potential to activates multiple secondary messenger pathways |
|
|
Term
| types of secondary messengers of GPCRs |
|
Definition
| cAMP, cGMP, and inositol triphosphate (IP3) |
|
|
Term
| describe how multistep signal relay pathways allow or profound amplification of receptor-binding events. |
|
Definition
| One occupied receptor can activate several G-proteins which can yield multiple second messenger molecules that can activate multiple effector pathways |
|
|
Term
| what are G-proteins and describe their subunits |
|
Definition
| they are small membrane-associated proteins with GTPase activity. Made up of an alpha, beta, and gamma subunit. The activated alpha subunit is what conducts the signaling |
|
|
Term
| specifics of the alpha subunit |
|
Definition
| has GTPase activity.N ormally bound to GDP. Receptor binding causes alpha to interact with G-protein partner. Binds GTP and releases from complex |
|
|
Term
|
Definition
| Principal ones are cAMP and IP3. Duration of activity limited by GTPase activity. Once GTP converted to GDP, subunit loses ability to signal then redocks with G-beta/gamma complex |
|
|
Term
| general cAMP signaling pathway |
|
Definition
| GPCR receptor binds ligand (neurotransmitter/hormone), receptor conformation change and interacts with G-protein complex, alpha subunit releases GDP and binds GTP, alpha subunit breaks from beta-gamma complex, alpha binds adenylyl cyclase, cAMP produced from adenylyl cyclase membrane protein. |
|
|
Term
|
Definition
| kinase A (PKA), which phosphorylates and modifies functin of variety of intraceullar proteins, enzymes, ion channels, and pumps |
|
|
Term
| potential of cAMP pathway |
|
Definition
| pathway has "tremendous" singaling amplification so many checks are in place to limit effects |
|
|
Term
| what counters the activity of adenyly cyclase |
|
Definition
| phosphodiesterase, which converts cAMP to 5'-AMP |
|
|
Term
|
Definition
| hormone binds GPCR receptor, receptor interacts with alpha-beta-gamma complex, alpha release GDP and binds GTP, active alpha activates phospholipase C, active phopholipase C PIP2 to IP3 and diacylglycerol, IP3 binds receptor on ER and releases Ca2+, Ca2+ activates protein kinase C, protein kinase C phosphorylates proteins which cause cellular responses. |
|
|
Term
|
Definition
|
|
Term
|
Definition
| the formation of IP3 and DAG from PIP2 |
|
|
Term
|
Definition
| ER, which releases Ca2+ into cytosol |
|
|
Term
|
Definition
| calmodulin (CaM) which mediates Ca2+ activation of enzymes and other intracellular effectors |
|
|
Term
| what is the activity of protein kinase C usually associated with |
|
Definition
| muscle contraction and salivary secretion |
|
|
Term
| what is the most common type of enzyme associated receptor |
|
Definition
| tyrosine kinases (TRKs) which are mostly single-peptide chains that associate after ligand binding |
|
|
Term
| activation of enzyme-associated receptors |
|
Definition
| Hormones/other messengers bind extracellularly to peptide chain. Conformational change occurs = dimerization. Intracellular portion of each monomer contains kinase domain. Dimerization brings 2catalytic domains into contact and they phosphorylate each other. Receptor complex activated which begins signaling |
|
|
Term
| enzyme-associated receptor signlaing |
|
Definition
| Mitogen-activated protein (MAP) kinase cascade is common type. Adapter protein mediates between receptor and intracellular effector. Common adapter proteins include Src homology domains. SH2-Recognizes phosphorylated tyrosine domains on activated TRK and allows adapter protein to bind signaling complexs |
|
|
Term
| what is the 4th type of class of intracellular receptors and what are they for |
|
Definition
| they are all TS factors that influence cell function by binding to DNA and altering expression of genes. They are for thyroid and steroid hormones |
|
|
Term
| are intracellular receptors cytoplasmic or nuclear? |
|
Definition
| both, muthafucka, but the cytoplasmic receptors are usually bound to HSPs which get displaced by steroid binding which causes conformational change, nigga |
|
|
Term
| where do intracellular receptors translocate to in the cell? |
|
Definition
| to the nucleus which binds to a hormone resopnse element which influence gene expression |
|
|
