Just as a reminder, what PR and IR means ( wikipedia, quite simple!)

Investor Relations (IR) is a strategic management responsibility that integrates finance, communication, marketing and securities law compliance to enable the most effective two-way communication between a company, the financial community, and other constituencies, which ultimately contributes to a company's securities achieving fair valuation. Many larger publicly traded companies now have dedicated IR officers (IROs), who oversee most aspects of shareholder meetings, press conferences, private meetings with investors, (known as "one-on-one" briefings), investor relations sections of company websites, and company annual reports. Public relations (PR) are the practice of managing the flow of information between an individual or an organization and the public. Public Relations is similar to Analyst Relations, Investor Relations and Public Affairs depending on the firm, organization    

"Public relations are a strategic communication process that builds mutually beneficial relationships between organizations and their publics."

Public relations can also be defined simply as the practice of managing communication between an organization and its publics.