Stimulation of intestinal basolateral membrane calcium-pump activity by recombinant synthetic calbindin-D9k and specific mutants.
Calcium transport by the Ca2(+)-pumping ATPase in rat duodenal basolateral-enriched membrane vesicles was stimulated by synthetic calbindin-D9k in a similar fashion to the purified natural protein. In order to elucidate the mechanism of this effect, various synthetic mutant proteins were studied. Proteins with modifications to the N-terminal Ca2(+)-binding domain, or to a cluster of negatively-charged surface residues had altered Ca2(+)-binding but these changes did not affect the stimulation of vesicular Ca2+ transport. It appears that these domains are not essential for the interaction between calbindin-D9k and the intestinal basolateral Ca2(+)-pump.
Walters
J R
JR
Gastroenterology Unit, United Medical School, London, U.K.
Howard
A
A
Charpin
M V
MV
Gniecko
K C
KC
Brodin
P
P
Thulin
E
E
Forsén
S
S
D000818:Animals; D001693:Biological Transport, Active; D064026:Calbindins; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism*; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004386:Duodenum / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009154:Mutation; D051381:Rats; D011994:Recombinant Proteins / Q000494:pharmacology; D064030:S100 Calcium Binding Protein G / Q000235:genetics / Q000494:pharmacology*
D064026:Calbindins; D015220:Calcium Channels; D011994:Recombinant Proteins; D064030:S100 Calcium Binding Protein G; C576508:S100g protein, rat; D002118:Calcium