The calcium sensor protein visinin-like protein-1 modulates the surface expression and agonist sensitivity of the alpha 4beta 2 nicotinic acetylcholine receptor.
The calcium sensor protein visinin-like protein-1 (VILIP-1) was isolated from a brain cDNA yeast two-hybrid library using the large cytoplasmic domain of the alpha4 subunit as a bait. VILIP-1 is a myristoylated calcium sensor protein that contains three functional calcium binding EF-hand motifs. The alpha4 subunit residues 302-339 were found to be essential for the interaction with VILIP-1. VILIP-1 coimmunopurified with detergent-solubilized recombinant alpha4beta2 acetylcholine receptors (AChRs) expressed in tsA201 cells and with native alpha4 AChRs isolated from brain. Coexpression of VILIP-1 with recombinant alpha4beta2 AChRs up-regulated their surface expression levels approximately 2-fold and increased their agonist sensitivity to acetylcholine approximately 3-fold. The modulation of the recombinant alpha4beta2 AChRs by VILIP-1 was attenuated in VILIP-1 mutants that lacked the ability to be myristoylated or to bind calcium. Collectively, these results suggest that VILIP-1 represents a novel modulator of alpha4beta2 AChRs that increases their surface expression levels and agonist sensitivity in response to changes in the intracellular levels of calcium.
Neuroscience Center of Excellence, Louisiana, New Orleans 70112, USA.
Lin
L
Lin
Elisabeth M
EM
Jeanclos
Magdalen
M
Treuil
Karl-Heinz
KH
Braunewell
Eckart D
ED
Gundelfinger
Rene
R
Anand
D000818:Animals; D002135:Calcium-Binding Proteins / Q000032:analysis / Q000502:physiology*; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000032:analysis; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D009419:Nerve Tissue Proteins / Q000032:analysis / Q000502:physiology*; D051596:Neurocalcin; D018722:Nicotinic Agonists / Q000494:pharmacology*; D011233:Precipitin Tests; D051381:Rats; D017207:Rats, Sprague-Dawley; D044169:Receptors, Calcium-Sensing; D011978:Receptors, Nicotinic / Q000032:analysis* / Q000187:drug effects; D011994:Recombinant Proteins / Q000187:drug effects; D014162:Transfection; D014981:Xenopus
D002135:Calcium-Binding Proteins; D009419:Nerve Tissue Proteins; D051596:Neurocalcin; D018722:Nicotinic Agonists; D044169:Receptors, Calcium-Sensing; D011978:Receptors, Nicotinic; D011994:Recombinant Proteins; C496688:VSNL1 protein, human; C496690:Vsnl1 protein, rat; C403531:nicotinic receptor alpha4beta2; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases