PMID- 10075700
OWN - NLM
STAT- MEDLINE
DCOM- 19990415
LR  - 20190508
IS  - 0021-9258 (Print)
IS  - 0021-9258 (Linking)
VI  - 274
IP  - 12
DP  - 1999 Mar 19
TI  - Calmodulin-binding sites on adenylyl cyclase type VIII.
PG  - 8012-21
AB  - Ca2+ stimulation of adenylyl cyclase type VIII (ACVIII) occurs through loosely
      bound calmodulin. However, where calmodulin binds in ACVIII and how the binding
      activates this cyclase have not yet been investigated. We have located two
      putative calmodulin-binding sites in ACVIII. One site is located at the N
      terminus as revealed by overlay assays; the other is located at the C terminus,
      as indicated by mutagenesis studies. Both of these calmodulin-binding sites were 
      confirmed by synthetic peptide studies. The N-terminal site has the typical motif
      of a Ca2+-dependent calmodulin-binding domain, which is defined by a
      characteristic pattern of hydrophobic amino acids, basic and aromatic amino
      acids, and a tendency to form amphipathic alpha-helix structures. Functional,
      mutagenesis studies suggest that this binding makes a minor contribution to the
      Ca2+ stimulation of ACVIII activity, although it might be involved in calmodulin 
      trapping by ACVIII. The primary structure of the C-terminal site resembles
      another calmodulin-binding motif, the so-called IQ motif, which is commonly
      Ca2+-independent. Mutagenesis and functional assays indicate that this latter
      site is a calcium-dependent calmodulin-binding site, which is largely responsible
      for the Ca2+ stimulation of ACVIII. Removal of this latter calmodulin-binding
      region from ACVIII results in a hyperactivated enzyme state and a loss of Ca2+
      sensitivity. Thus, Ca2+/calmodulin regulation of ACVIII may be through a
      disinhibitory mechanism, as is the case for a number of other targets of
      Ca2+/calmodulin.
FAU - Gu, C
AU  - Gu C
AD  - Neuroscience Program and Department of Pharmacology, University of Colorado
      Health Sciences Center, Denver, Colorado 80262, USA.
FAU - Cooper, D M
AU  - Cooper DM
LA  - eng
GR  - GM 32483/GM/NIGMS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - J Biol Chem
JT  - The Journal of biological chemistry
JID - 2985121R
RN  - 0 (Calmodulin)
RN  - E0399OZS9N (Cyclic AMP)
RN  - EC 4.6.1.1 (Adenylyl Cyclases)
RN  - EC 4.6.1.1 (adenylyl cyclase 8)
RN  - SY7Q814VUP (Calcium)
SB  - IM
MH  - Adenylyl Cyclases/chemistry/genetics/*metabolism
MH  - Amino Acid Sequence
MH  - Binding Sites
MH  - Blotting, Western
MH  - Calcium/metabolism
MH  - Calmodulin/*metabolism
MH  - Cell Line
MH  - Cyclic AMP/metabolism
MH  - Humans
MH  - Molecular Sequence Data
MH  - Mutagenesis, Site-Directed
MH  - Protein Structure, Secondary
EDAT- 1999/03/13 00:00
MHDA- 1999/03/13 00:01
CRDT- 1999/03/13 00:00
PHST- 1999/03/13 00:00 [pubmed]
PHST- 1999/03/13 00:01 [medline]
PHST- 1999/03/13 00:00 [entrez]
AID - 10.1074/jbc.274.12.8012 [doi]
PST - ppublish
SO  - J Biol Chem. 1999 Mar 19;274(12):8012-21. doi: 10.1074/jbc.274.12.8012.