Lecture 45 Flashcards
(11 cards)
Nitric Oxide is an example of a gaseous messenger that acts by _____ signaling.
Paracrine
Ligands that can permeate the cell membrane bind receptors in the cytosol or within the nucleus. These receptors have three key domains: 1. The _____ binding domain. 2. The ____ binding domain. 3. The _____ activating domain.
Ligand
DNA
Transcription
Acetyl Choline binds ___-____ coupled receptors, allowing the flow of _____ when it binds. Some receptors are enzyme-coupled, which means when the ligand binds, the ______ portion carries out enzymatic activity (typically phosphorylation.) ___ dimer receptors (the kind insulin and epidermal growth factor bind) are examples of this.
Ion-channel
Ions
Intracellular
Tyrosine
Tyrosine kinase receptors activate protein kinases that phosphorylate ____ and _____ residues. Remember the Ras –> Raf –> MapK –> transcription factor ish from Advis
Serine and Threonine
For G-protein coupled receptors, like the one that binds Epi, binding of the ligand causes a comformational change –> ___ subunit of the G-protein replaces ____ with ____ –> activates ____ ____ –> converts ATP to cAMP –> cAMP acts as a second messenger on the regulatory subunit of its target, PKA –> the ____ unit dissociates from the regulatory unit and acts as a protein kinase that phosphorylates other proteins. Inactivation of PKA occurs as a result of cAMP breakdown to AMP by cAMP-________.
Alpha
GDP
GTP
Adenylyl Cyclase (AC)
Catalytic
cAMP-phosphodiesterase
The way G-proteins inactivate is through intrinsic GTPase activity of the ____ subunit, which hydrolyses GTP to GDP, so the subunit can re-associate with the other two. Keep in mind the ___ and ___ subunits can open K+ channels to cause cell hyperpolarization.
Alpha
Beta
Gamma
____, ____, and ____ are the three AA residues that are phosphorylated by kinases bc kinases phosphorylate OH groups, which these AAs have in their side chains Most kinases recognize the ______ structure (AA sequence) of proteins as their target. Kinases are more regulated than ______, which dephosphorylate.
Serine
Threonine
Tyrosine
Primary
Phosphatases
Epi, norepi, and ____ are activators of Gs class of g-proteins. Norepi, _______, and opiates are activators of Gi class. Epi and ____ activate the Gq class.
Glucagon
Prostaglandins
ACh
Ca++ is moved out of the cell in a couple ways. One involves an antiport mech in which 3 ___ are moved into the cell (down its gradient) and 1 Ca++ is moved out (up its gradient). Another involves an ATP requiring pump, which is present both at the plasma membrane and the ____ membrane (moves Ca++ into this organelle).
Na+
ER
PIP2 is the precursor molecule that is converted into _____ and _____ by phospholipase C. ___ activates Protein Kinase C, while ____ causes release of Ca++ from the ER.
IP3
DAG
DAG
IP3
______ is a protein that binds 4 Ca++ molecules. When it binds 4 Ca++, _____ can bind and activate Ca++/_____-dependent protein kinases, which mediate many functions including smooth and cardiac muscle contraction.
Calmodulin
Calmodulin
Calmodulin
