Contacting potential postdoc advisor in open announcements I am intending to apply for postdoc at an institution. I already am acquainted with the potential adviser (we know each other). I already have contacted him expressing my interest in joining his group. However, the institution calls for regular open announcements for postdoc positions and I am particularly interested to pursue under his supervision only. So he advised in his reply to check for the open announcement. Now the applications are called for and a research proposal is needed to apply. I have made a proposal that is in sync with his area of interest (in which I am interested too). 

I am really confused whether it would be wise or even need to email a copy of my research proposal to him, as the institution hires postdoc candidates through a common application procedure. Or is it enough that I just apply via institutional procedures and then send an email informing him that I did ?
Apply via the university system first - most likely you will have to do that for HR to even consider you a candidate. Then, reach out to this person and ask him or her if they can and want to receive a copy of your proposal. Some universities have rules when there is an open announcement regarding what they can receive from candidates and how they receive it (standard email versus the online submission system). Plus, if the person is swamped with work, getting an unsolicited research proposal via email may be overwhelming for him or her and not helpful for you. If he or she wants to work with you and knows that you applied, they can advocate to administration and/or committees about your merit as a candidate.  Good luck!