Specific association of the proto-oncogene product pp60c-src with an intracellular organelle, the PC12 synaptic vesicle.
The protein product of the proto-oncogene c-src is a membrane-associated tyrosine kinase of unknown function. Identification of pp60c-src target membranes may elucidate the function of the c-src protein. The available evidence indicates that pp60c-src associates with distinct membranes within single cell types and has different distributions in different cell types. Our experiments demonstrate targeting of pp60c-src to an isolatable and biochemically identified membrane fraction in the neuroendocrine cell line PC12. The c-src protein was found to be specifically associated with synaptic vesicles since: (a) the pp60c-src immunofluorescent pattern overlapped with a synaptic vesicle marker, synaptophysin; (b) a significant proportion (44%) of the pp60c-src from PC12 but not fibroblast postnuclear supernatants was recovered in a small vesicle fraction; (c) an anti-synaptophysin cytoplasmic domain antibody immunodepleted all of the pp60c-src vesicles in this fraction, and (d) pp60c-src copurified during a 100-fold purification of PC12 synaptic vesicles. These results suggest a role for the c-src protein in the regulation of synaptic vesicle function.
Linstedt
A D
AD
Program in Neuroscience, University of California, San Francisco 94143-0534.
Vetter
M L
ML
Bishop
J M
JM
Kelly
R B
RB
D000818:Animals; D005455:Fluorescent Antibody Technique; D015151:Immunoblotting; D016716:PC12 Cells; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000032:analysis*; D013572:Synaptic Vesicles / Q000737:chemistry*; D016708:Synaptophysin / Q000032:analysis
D016708:Synaptophysin; D016392:Proto-Oncogene Proteins pp60(c-src)