Lesson 6
endocrine signaling
usually a long distance between signaling cell and target cells secreted signaling cells travel throughout the body where appropriate slower but longer lasting response
phosphotase
any of a number of enzymes that removes a phosphate group from a protein, reversing the action of a kinase
G protein-coupled receptors(GPCR)
A receptor that acts through a heterotrimeric (3 component) G protein to activate effector proteins. the effector proteins then function as enzymes to produce second messengers such as cAMP or IP3
autophosphorylation
Autophosphorylation is a type of post-translational modification of proteins. It is generally defined as the phosphorylation of the kinase by itself. In eukaryotes, this process occurs by the addition of a phosphate group to serine, threonine or tyrosine residues within protein kinases, normally to regulate the catalytic activity.
Choose the statement which is NOT true: Signaling occurs within multicellular organisms and between single-cell organisms Cells use receptor proteins to detect signals Cells respond to all signal molecules (ligands) that they come in contact with Extracellular signals are converted into intracellular signals (signal transduction)
Cells respond to all signal molecules (ligands) that they come in contact with
Which would be the correct sequence of events for a G-Coupled Protein Receptor (GPCR) signal transduction pathway? Ligand binds to GCPR - Receptor; G-Protein; effector protein; cellular response Ligand binds to GProtein; activates receptor; effector protein; cellular response Ligand binds to effector protein; activates G protein; cellular response. Ligand binds to GCPR - "deactivation" of G protein; G protein subunit deactivates effector protein; cellular response
Ligand binds to GCPR - Receptor; G-Protein; effector protein; cellular response
PIP2
Phosphatidylinositol 4,5-bisphosphate or PtdIns(4,5)P2, also known simply as PIP2, is a minor phospholipid component of cell membranes. PtdIns(4,5)P2 is enriched at the plasma membrane where it is a substrate for a number of important signaling proteins.
Which is NOT true of phosphorylation? Kinase uses ATP to add a phosphate to select amino acids RTK's operate by autophosphorylation, which then leads to a cellular response Phosphorylation will always turn the "target" protein on; dephosphorylation will always turn the "target" protein off. Kinase cascades can amplify signals in the cell
Phosphorylation will always turn the "target" protein on; dephosphorylation will always turn the "target" protein off.
Ras
Ras is a family of related proteins which is expressed in all animal cell lineages and organs. All Ras protein family members belong to a class of protein called small GTPase, and are involved in transmitting signals within cells (cellular signal transduction).
Choose the cell to cell signaling mechanism that best represents how our nervous system operates: Direct contact Paracrine signaling Endocrine signaling Synaptic signaling
Synaptic signaling
second messenger
The term second messenger was coined upon the discovery of these substances in order to distinguish them from hormones and other molecules that function outside the cell as "first messengers" in the transmission of biological information.
signal amplification
The use of specific detection methodologies to directly increase the signal in proportion to the amount of target in the reaction. Examples include the use of branched DNA probes that contain a reporter group or enzyme amplification.
MAP kinase
any of a class of protein kinases that activiate transcription factors to alter gene expression. a mitogen is any molecule that stimulates cell division. MAP kinases are activated by kinase cascades
Adaptor proteins
any of a class of proteins that acts as a link between a receptor and other proteins to initiate cell transduction
adenylyl cyclase is activated by calcium cAMP a G protein protein kinase A
a G protein
cell surface receptors
a cell surface protein that binds a single molecule and converts the extracellular signal into an intracellular one
receptor tyrosine kinase (RTK)
a diverse group of membrane rececptors that when activated have kinase enzymatic activity. specifically, they phosphorylate proteins on tyrosine. their activiation can lead to diverse cellular responses
cAMP
a form of adenosine monophosphate (AMP) in which the atoms of the phosphate group form a ring; found in almost all organisms, cAMP functions as an intracellular second messenger that regulates a diverse array of metabolic activities
.calmodulin
a protein that binds calcium and is involved in regulating a variety of activities in cells.
diaclyglycerol (DAG)
a second messenger that is released, along with ip3, when phospholipase C cleaves PIP2. DAG can have a variety of cellular effects through activation of protein kinases
ligand
a signaling molecule that binds to a specific receptor protein, initiating signal transduction in cells
paracrine signaling
a type of chemical signaling between cells in which the effects are local and short lived
phosphorylation
chemical rxn resulting in the addition of a phosphate group to an organic molecule. phosphorylation of ADP yields ATP. many proteins are also activated or inactivated by phosphorylation
TF: endrocrine signaling is typically faster than paracrine signaling
false
TF: every cell in your body can respond to every signal molecule in your body
false
TF: phosphorylation of an enzyme will always increase the activity of that enzyme
false
kinase
kinase is an enzyme that catalyzes the transfer of phosphate groups from high-energy, phosphate-donating molecules to specific substrates.
A researcher is trying to produce a new cancer drug to be tested on small tumors. The tumor has to be localized in a small area of the body and cannot have metastasized (spread to other areas of the body). Furthermore, this drug must prohibit the signaling from one tumor cell to another tumor cell. Given the above information, this new drug will prohibit autocrine signaling between tumor cells. endocrine signalizing between tumor cells. direct physical contact between tumor cells. paracrine signaling between tumor cells.
paracrine signaling between tumor cells.
A mutation that inactivates a ____ may prevent a signal pathway from being turned off second messenger G protein receptor protein phosphotase
phosphotase
IP3 (inositol triphosphate)
second messenger produced by the cleavage of phosphatidylinositol biophosphate
effector
used to describe an organ, a gland, or a muscle that responds to a nerve impulse.
signal transduction
the events that occur within a cell on receipt of a signal sequence of polypeptide, and then docks with a receptor that forms a channel in the ER membrane. in this way the polypeptide is released into the lumen of the ER
dephosphorylation
the removal of a phosphate group, usually by a phosphatase enzyme. many proteins can be activated or inactivated by dephosphorylation
direct contact signaling
touching, fastest, gap junctions creates pores in the membranes of adjacent cells