Evidence for a role of the N-terminal domain in subcellular localization of the neuronal connexin36 (Cx36).
The expression and functional properties of connexin36 (Cx36) have been investigated in two neuroblastoma cell lines (Neuro2A, RT4-AC) and primary hippocampal neurons transfected with a Cx36-enhanced green fluorescent protein (EGFP) expression vector. Transfected cells express Cx36-EGFP mRNA, and Cx36-EGFP protein is localized in the perinuclear area and cell membrane. Upon differentiation of cell lines, Cx36-EGFP protein was detectable in processes with both axonal and dendritic characteristics. Small gap junction plaques were found between adjacent cells, and electrophysiological recordings demonstrated that the electrical properties of these gap junctions were virtually indistinguishable from those reported for native Cx36. Mutagenesis of Cx36 led to the identification of a structural element that interferes with normal protein localization. In contrast, site directed mutagenesis of putative protein phosphorylation motifs did not alter subcellular localization. This excludes phosphorylation/dephosphorylation as a major regulatory step in Cx36 protein transport.
Zoidl
G
G
Department of Neuroanatomy and Molecular Brain Research, Ruhr-University-Bochum, Germany. georg.zoidl@ruhr-uni-bochum.de
Meier
C
C
Petrasch-Parwez
E
E
Zoidl
C
C
Habbes
H-W
HW
Kremer
M
M
Srinivas
M
M
Spray
D C
DC
Dermietzel
R
R
D000818:Animals; D000831:Animals, Newborn; D002450:Cell Communication / Q000502:physiology*; D002451:Cell Compartmentation / Q000502:physiology*; D002490:Central Nervous System / Q000378:metabolism* / Q000648:ultrastructure; D017630:Connexins / Q000235:genetics / Q000378:metabolism*; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D019922:GAP-43 Protein / Q000378:metabolism; D017629:Gap Junctions / Q000378:metabolism* / Q000648:ultrastructure; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D008854:Microscopy, Electron; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D016297:Mutagenesis, Site-Directed / Q000235:genetics; D009474:Neurons / Q000378:metabolism* / Q000648:ultrastructure; D011494:Protein Kinases / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000502:physiology; D021381:Protein Transport / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D011993:Recombinant Fusion Proteins; D015398:Signal Transduction / Q000502:physiology; D014407:Tumor Cells, Cultured; D000097004:Gap Junction delta-2 Protein
D017630:Connexins; D005136:Eye Proteins; D019922:GAP-43 Protein; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D008869:Microtubule-Associated Proteins; D011494:Protein Kinases; D011993:Recombinant Fusion Proteins; D000097004:Gap Junction delta-2 Protein