ATyr Pharma Inc., a company that treats diseases of the immune system, has appointed biotech veteran David Weiner as its chief medical officer.

Weiner has held leadership positions at San Diego’s Acadia Pharmaceuticals Inc., German pharma company Merck Serono, and Massachuesetts-based Proteostasis Therapeutics Inc.

Weiner, a physician by training, has a strong development background and clinical experience that will help aTyr “at a key time for advancing our pipeline of therapeutics in the rare disease area,” CEO John Mendlein said in a statement.

The company also appointed biotech pioneer Ed Penhoet to its board of directors. Penhoet is a director at venture fund Alta Partners, one of aTyr’s investors, and hhe as served on a number of boards — most notably President Obama’s President's Council of Advisors on Science and Technology.