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.
Lin
Lin
L
Neuroscience Center of Excellence, Louisiana, New Orleans 70112, USA.
Jeanclos
Elisabeth M
EM
Treuil
Magdalen
M
Braunewell
Karl-Heinz
KH
Gundelfinger
Eckart D
ED
Anand
Rene
R
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