1. Eric Niederhoffer SIU-SOM
11/27/2018
Olfaction
Olfaction signaling
Cyclic nucleotide gated channels
Inositol trisphosphate/Ca2+/Protein kinase C
Eric Niederhoffer
SIU-SOM

2. Olfaction O BP OR AC Golfbg a GDP a GTP RK CNGC cAMP ATP CaM GTP GDP
11/27/2018
Olfaction O BP OR AC
Golfbg a
GDP a
GTP RK
CNGC
cAMP
ATP
CaM
GTP
GDP
5’-AMP
PDE
Ca2+
ORi RK
OR: odorant receptor O: odorant
BP: binding protein Golf: G protein
GDP: guanosine diphosphate GTP: guanosine triphosphate
AC: adenylate cyclase ATP: adenosine triphosphate
cAMP: cyclic adenosine monophosphate CNGC: cyclic nucleotide-gated channel
CaM: calmodulin; decreases CNGC sensitivity PDE: phosphodiesterase
5’AMP: 5’-adenosine monophosphate RK: receptor kinase
PLC: phospholipase C ER: endoplasmic reticulum
PIP2: phosphatidylinositol-4,5-bisphosphate IP3: inositol-1,4,5-trisphosphate
PKC: protein kinase C; increases sensitivity of AC and CNGC
There appears to be a 3rd pathway that utilizes a guanylyl cyclase (cGMP) receptor.
Odorant cells are one of the few cells where [Cl-] is greater inside than outside.
-arrestin binds the phosphorylated receptor AND appears to recruit phosphodiesterase to degrade the cAMP signal
Kallmann syndrome, a rare hypogonadotropic hypogonadism
(IP3)
Cl-
Ca2+
GTP
GDP Gq
GDP
GTP ER
PKC OR
PLC
PIP2 O BP

3. Review Questions Which ions and ion channels are used for olfaction?
11/27/2018
Review Questions
Which ions and ion channels are used for olfaction?
Which signal transduction pathways are used for olfaction (enzymes, second messengers, receptors)?