The calsyntenins--a family of postsynaptic membrane proteins with distinct neuronal expression patterns.
We have identified two novel postsynaptic membrane proteins that are highly similar to calsyntenin-1 in their extracellular parts but vary considerably in their cytoplasmic segment. Calsyntenin-1 has recently been identified in our lab as a postsynaptic membrane protein with a highly acidic cytoplasmic segment with putative Ca(2+)-binding capacity (Vogt et al., 2001, Mol. Cell. Neurosci. 17: 151-166). Based on their structural similarity to calsyntenin-1, we have called the novel proteins calsyntenin-2 and -3, respectively. By immunoelectron microscopy, the calsyntenin protein family was localized in the postsynaptic membrane of excitatory central nervous system (CNS) synapses. In situ hybridization analysis revealed that calsyntenin-1 was abundant in most neurons of the CNS with relatively little variation in its expression level. Calsyntenin-2 and -3 expressions varied much more with highest levels in GABAergic neurons. Based on their distinct expression patterns and the differences in their cytoplasmic segments, we suggest a cell-type-specific functional role for the three calsyntenins in excitatory synaptic transmission.
Hintsch
G
G
Institute of Biochemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland.
Zurlinden
A
A
Meskenaite
V
V
Steuble
M
M
Fink-Widmer
K
K
Kinter
J
J
Sonderegger
P
P
D000818:Animals; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D002478:Cells, Cultured; D002490:Central Nervous System / Q000378:metabolism* / Q000648:ultrastructure; D002878:Chromosomes, Human, Pair 1 / Q000235:genetics; D002881:Chromosomes, Human, Pair 12 / Q000235:genetics; D002893:Chromosomes, Human, Pair 3 / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D009474:Neurons / Q000378:metabolism* / Q000648:ultrastructure; D012333:RNA, Messenger / Q000378:metabolism; D011817:Rabbits; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013570:Synaptic Membranes / Q000378:metabolism* / Q000648:ultrastructure; D009435:Synaptic Transmission / Q000502:physiology*
C503225:CLSTN1 protein, human; C472551:CLSTN2 protein, human; C472553:CLSTN3 protein, human; D002135:Calcium-Binding Proteins; C503227:Clstn1 protein, mouse; C472554:Clstn3 protein, mouse; D008565:Membrane Proteins; D012333:RNA, Messenger; C472552:calsyntenin-2, mouse