Expression of postsynaptic density proteins of the ProSAP/Shank family in the thymus.
PSD95-DLG-ZO1 domain-containing proteins of the ProSAP/Shank family are major scaffolding proteins of the neuronal postsynaptic density which play a pivotal role in the linkage of membrane receptors to downstream signal effectors and the actin-based cytoskeleton. Recently, ProSAP1/Shank2 has also been localized in various non-neuronal cells where it may fulfill similar functions as in neurons. We now complement these data by the study of ProSAP/Shank expression at the mRNA and protein level in a primary lymphoid organ, i.e., the thymus. Transcripts for ProSAP1/Shank2, the spliceoform Shank2E, and ProSAP2/Shank3 could be clearly detected in the thymus. Western blot and immunocytochemical analyses verified the presence of ProSAP1/Shank2 and ProSAP2/Shank3 proteins in thymic tissue. Immunoreactivity was concentrated in the whole peripheral cytoplasm of thymocytes underneath the plasma membrane. Discrete subplasmalemmal areas of pronounced ProSAP/Shank immunoreactivity could be demonstrated inside several thymocytes by confocal laser scanning microscopy. Our results establish ProSAP/Shank as a constituent of the cell cortex of thymocytes and thus lead to the hypothesis that ProSAP/Shank proteins serve as a platform for the coordination of membrane receptor-dependent signal transduction in immune cells.
Redecker
Peter
P
Department of Cell Biology, Center of Anatomy, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany. redecker.peter@mh-hannover.de
Bockmann
Jürgen
J
Böckers
Tobias M
TM
D048868:Adaptor Proteins, Signal Transducing / Q000032:analysis* / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000737:chemistry; D005455:Fluorescent Antibody Technique; D007150:Immunohistochemistry; D009419:Nerve Tissue Proteins / Q000032:analysis / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013950:Thymus Gland / Q000737:chemistry* / Q000166:cytology / Q000276:immunology
D048868:Adaptor Proteins, Signal Transducing; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; C485686:Shank2 protein, rat; C120532:Shank3 protein, rat