Signaling and receptor-mediated endocytosis
Return to GOC Main Page
Return to Signaling Main Page [[1]]
PROBLEM
Receptors are involved in receptor-mediated endocytosis (eg LDL receptors, vitellogenin receptors). Are these signaling receptors, if all they are doing is resulting in endocytosis of the ligand? Is this any different to a transporter moving its substrate, or an enzyme recognizing its substrate?
For a summary of the problems, see slides 61-64 in the following presentation from the February 2011 signaling workshop.
BACKGROUND
RELATED SOURCEFORGE ITEM
Tanya's SF item suggests splitting the receptors into those that signal and those that endocytose their substrate:
https://sourceforge.net/tracker/?func=detail&aid=2894756&group_id=36855&atid=440764
PROPOSAL
-I think we are agreed that RME is not a signaling event, and that the first step doesn't count as signal transduction.
-Internalization of the ligand (and/or receptor) can of course regulate a signaling event as it regulates how much ligand or receptor is available for signaling.
Restricting 'receptor activity ; GO:0004872' to those receptors that signal [2] will create the split of signaling receptors and 'other receptors'.
Q: Do we want a generic 'receptor activity' term in MF? If so, how would it be defined other than 'binding'?
molecular_function --%receptor activity ; GO:NEW ----%signaling receptor activity ; GO:0004872 ----%receptor activity involved in endocytosis ; GO:NEW ------%lipoprotein particle receptor activity ; GO:0030228 ------%vitellogenin receptor activity ; GO:0008196 receptor activity ; GO:NEW Combining with an extracellular or intracellular molecule or signal to initiate a change in cell activity.
signaling receptor activity ; GO:0004872 Combining with a signal to initiate a change in cell activity. A signal is any variable property or parameter that serves to convey information, and may be a physical entity such as a gene product or small molecule, a photon, or a change in state such as movement or voltage change. is_a: signal transducer activity synonym: receptor involved in signal transduction receptor activity involved in endocytosis ; GO:NEW Combining with a extracellular molecule on the surface of the cell and acting to internalize the molecule. part_of: receptor-mediated endocytosis ; GO:0006898 synonym: endocytotic receptor activity