The cysteine-rich with EGF-like domains 2 (CRELD2) protein interacts with the large cytoplasmic domain of human neuronal nicotinic acetylcholine receptor alpha4 and beta2 subunits.
Using a yeast two-hybrid screening we report the isolation of a novel human protein, hCRELD2beta, that interacts specifically with the large cytoplasmic regions of human nicotinic acetylcholine receptor (nAChR) alpha4 and beta2 subunits, both in yeast cells and in vitro. This interaction is not detected with nAChR alpha7 and alpha3 subunits. The hCRELD2 gene encodes for multiple transcripts, likely to produce multiple protein isoforms. A previously reported one has been renamed as CRELD2alpha. Isoforms alpha and beta are expressed in all tissues examined and have the same N-terminal and central regions but alternative C-terminal regions. Both isoforms interact with the alpha4 subunit. Within this subunit the interaction was localized to the N-terminal region of the large cytoplasmic loop. The CRELD2beta protein is present at the endoplasmic reticulum where colocalized with alpha4beta2 nAChRs upon cell transfection. Immunohistochemistry experiments demonstrated the presence of CRELD2 in the rat brain at sites where alpha4beta2 receptors have been previously detected. Labeling was restricted to neuronal perikarya. Finally, CRELD2 decreases the functional expression and impairs membrane transport of alpha4beta2 nAChRs in Xenopus leavis oocytes, without affecting alpha3beta4 and alpha7 nAChR expression. These results suggest that CRELD2 can act as a specific regulator of alpha4beta2 nAChR expression.
Ortiz
José A
JA
Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Sant Joan d'Alacant, Alicante, Spain.
Castillo
Mar
M
del Toro
Eduardo Dominguez
ED
Mulet
José
J
Gerber
Susana
S
Valor
Luis M
LM
Sala
Salvador
S
Sala
Francisco
F
Gutiérrez
Luis M
LM
Criado
Manuel
M
D000595:Amino Acid Sequence; D015152:Blotting, Northern; D015153:Blotting, Western; D001923:Brain Chemistry / Q000502:physiology; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D002478:Cells, Cultured; D003545:Cysteine / Q000502:physiology*; D003593:Cytoplasm / Q000378:metabolism*; D018076:DNA, Complementary / Q000096:biosynthesis / Q000235:genetics; D004274:DNA, Recombinant / Q000096:biosynthesis / Q000235:genetics; D004721:Endoplasmic Reticulum / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D015723:Gene Library; D006801:Humans; D007150:Immunohistochemistry; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D009474:Neurons / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics; D017510:Protein Folding; D011978:Receptors, Nicotinic / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism; D014162:Transfection; D015003:Yeasts / Q000235:genetics; D001616:beta-Galactosidase / Q000378:metabolism
C507070:CRELD2 protein, human; D015815:Cell Adhesion Molecules; D018076:DNA, Complementary; D004274:DNA, Recombinant; D016326:Extracellular Matrix Proteins; D011978:Receptors, Nicotinic; C403531:nicotinic receptor alpha4beta2; D001616:beta-Galactosidase; D003545:Cysteine