SNAP-25 inhibits L-type Ca2+ channels in feline esophagus smooth muscle cells.
We recently reported that non-secretory gastrointestinal smooth muscle cells also possessed SNARE proteins, of which SNAP-25 regulated Ca(2+)-activated (K(Ca)) and delayed rectifier K(+) channels (K(V)). Voltage-gated, long lasting (L-type) calcium channels (L(Ca)) play an important role in excitation-contraction coupling of smooth muscle. Here, we show that SNAP-25 could also directly inhibit the L-type Ca(2+) channels in feline esophageal smooth muscle cells at the SNARE complex binding synprint site. SNARE proteins could therefore regulate additional cell actions other than membrane fusion and secretion, in particular, coordinated muscle membrane excitability and contraction, through their actions on membrane Ca(2+) and K(+) channels.
Ji
Junzhi
J
University Health Network, Toronto Western Hospital, Ont., M5T 2S8, Toronto, Canada.
Muinuddin
Ahmad
A
Kang
Youhou
Y
Diamant
Nicholas E
NE
Gaisano
Herbert Y
HY
D000818:Animals; D001665:Binding Sites; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D020746:Calcium Channels, L-Type / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism; D002415:Cats; D004947:Esophagus / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D066298:In Vitro Techniques; D008565:Membrane Proteins / Q000378:metabolism / Q000494:pharmacology*; D009130:Muscle, Smooth / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism / Q000494:pharmacology*; D011993:Recombinant Fusion Proteins / Q000378:metabolism / Q000494:pharmacology; D050600:SNARE Proteins; D050825:Synaptosomal-Associated Protein 25; D033921:Vesicular Transport Proteins
D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D011993:Recombinant Fusion Proteins; D050600:SNARE Proteins; D050825:Synaptosomal-Associated Protein 25; D033921:Vesicular Transport Proteins