Isoforms of Mammalian Adenylyl Cyclase: Multiplicities of Signaling

Table 1.

Regulatory Properties of Mammalian Adenylyl Cyclase Isoforms

AC Isoforma,b Chromosomal Location Tissue Distribution Regulation by G Protein Subunits Protein Kinases Calcium Effects Putative Function
BAT, brown adipose tissue; LTP, long-term potentiation.
a All isoforms except sAC are inhibited by P-site inhibitors.
b Forskolin stimulates human AC1-AC8, whereas AC9 is weakly stimulated by forskolin. sAC is not affected by forskolin.
c Cited reference numbers.
d Gβγ stimulation of AC isoforms is conditional upon Gαs co-activation.
e Inhibition determined by transfection only and could be an indirect Gβγ effect.
f Denotes Gαi family members Gαi1, Gαi2, Gαi3, and Gαz.
g Inhibited by calcineurin.
h Stimulated by bicarbonate.
AC1 7p12 (154)c Brain adrenal medulla Stimulated by Gαs Inhibited by Gβγ Inhibited by Gαo PKC: weak stimulation CaMKIV: inhibition Stimulated by Ca2+-CaM inhibition Learning, memory, LTP Synaptic plasticity
AC2 5p15 (155, 156) Brain, skeletal muscle, lung, heart Stimulated by Gαs Stimulated by Gβγd PKC: stimulation
AC3 2p22-p24 (157) Brain, olfactory epithelium Stimulation by Gαs PKC: weak stimulation CaMKII: inhibition Stimulated by Ca2+-CaM Olfaction
AC4 14q11.2 (156) Brain heart, kidney, liver, lung, BAT, uterus Stimulation by Gαs Stimulated by Gβγd PKC: inhibition
AC5 3q13.2-q21 (157) Heart, brain, kidney, liver, lung, uterus, adrenal, BAT Stimulation by Gαs Inhibited by Gβγe Inhibited by Gαif PKA: inhibition PKCα,ζ: stimulation Inhibited
AC6 12q12-q13 (157) Ubiquitous Stimulation by Gαs Inhibited by Gβγe Inhibited by Gαif PKA: inhibition PKC: inhibition Inhibited
AC7 16q12-q13 (158) Ubiquitous, highly expressed in brain Stimulation by Gαs Stimulated by Gβγd PKC: stimulation Drug dependency
AC8 8q24 (155, 156) Brain, lung (testis, adrenal, uterus, heart) Stimulation by Gαs Stimulated byCa2+-CaM Learning, memory, LTP, Synaptic plasticity
AC9g 16p13.3 (159) Brain, skeletal muscle Stimulation by Gαs
SACh 1q24 (24) Testis Not regulated by G protein subunits Sperm capacitation

This Article

  1. MI June 2002 vol. 2 no. 3 168-184