Isolation and characterization of vascular smooth muscle inositol 1,4,5-trisphosphate receptor.
myo-Inositol 1,4,5-trisphosphate (InsP3) receptor of porcine aorta was purified to near homogeneity and its biochemical properties were compared with those of cerebellar InsP3 receptor of the same animal species. The aortic InsP3 receptor consisted of equal amounts of two polypeptides with slightly differing molecular masses of around 240 kDa and was found to possess a single population of InsP3-binding site (Kd of 1.2 nM). The InsP3 receptor purified from porcine cerebellum was also comprised of two polypeptides. However, the molecular mass was slightly but definitely larger, being 250 kDa, and the amounts of the two polypeptides were not equal. The aortic InsP3 receptor cross-reacted with polyclonal antibody specific to type 1 InsP3 receptor as did the cerebellar InsP3 receptor. The aortic InsP3 receptor bound to calmodulin-Sepharose in a Ca(2+)-dependent manner, while the cerebellar InsP3 receptor did not. Reverse transcriptase-PCR analysis revealed two splicing variants of the type 1 InsP3 receptor in porcine aortic smooth muscle distinct from those of the type 1 InsP3 receptor of porcine cerebellum. The possible relevance of this difference to difference in calmodulin-binding property was discussed.
Islam
M O
MO
Department of Pharmacology, Niigata University School of Medicine, Japan.
Yoshida
Y
Y
Koga
T
T
Kojima
M
M
Kangawa
K
K
Imai
S
S
D000595:Amino Acid Sequence; D000818:Animals; D001011:Aorta; D001483:Base Sequence; D001665:Binding Sites; D015220:Calcium Channels / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism; D002531:Cerebellum / Q000378:metabolism; D002846:Chromatography, Affinity; D017869:Cyclic GMP-Dependent Protein Kinases / Q000378:metabolism; D017931:DNA Primers; D014644:Genetic Variation; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007700:Kinetics; D008969:Molecular Sequence Data; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D010766:Phosphorylation; D016133:Polymerase Chain Reaction; D012326:RNA Splicing; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D013552:Swine
D015220:Calcium Channels; D002147:Calmodulin; D017931:DNA Primers; D053496:Inositol 1,4,5-Trisphosphate Receptors; D018160:Receptors, Cytoplasmic and Nuclear; D015544:Inositol 1,4,5-Trisphosphate; D017869:Cyclic GMP-Dependent Protein Kinases