Position:

Chief Medical Officer

Location:

San Diego, CA

Status:

Full-Time, Exempt. This means you are paid for the job and not by the hour. Accordingly, you will not receive overtime pay if you work more than 8 hours in a work day or 40 hours in a workweek.

Reporting to:

John Mendlein, Ph.D., Executive Chairman and Chief Executive Officer

Base Salary Rate:

$13,958.34 semi-monthly (which equals $335,000.00 per year) less applicable withholdings, paid in accordance with Company’s normal payroll practices. Future adjustments in compensation, if any, will be made by the Company in its sole and absolute discretion.

Target Bonus:

Your annual target bonus will be 30% of your base salary with a range of 0-40% based upon the achievement of your individual goals, the achievement of team goals and the achievement of corporate goals. Your annual target bonus is subject to review and approval by the aTyr Board of Directors. Any bonus will be prorated based upon service in a year.

Equity:

Shortly after commencement of your employment with the Company, and subject to approval by the board of directors, you will be granted an option to purchase 916,035 shares of the Common Stock of the Company (the “Initial Option”) pursuant to the Company’s 2007 Stock Plan (the “aTyr Plan”). Subject to your continued full-time employment with the Company, the shares subject to the Initial Option shall vest over a six (6)

year period, with a one (1) year cliff, such that one-sixth (1/6) of the shares subject to the Initial Option shall vest on the first year anniversary of your employment start date and the remainder of the shares shall thereafter vest in equal monthly installments over the subsequent five (5) years. In addition, after commencement of your employment with the Company, and subject to approval by the board of directors, you will be granted an additional option to purchase 45,801 shares of the Common Stock of the Company (the “Additional Option” and together with the Initial Option, the “Options”) pursuant to the 2007 Stock Plan. Subject to your continued full-time employment with the Company, the shares subject to the Additional Option shall vest over a six (6) year period, with a one (1) year cliff, such that one-sixth (1/6) of the shares subject to the Additional Option shall vest on the first year anniversary of your employment start date and the remainder of the shares shall thereafter vest in equal monthly installments over the subsequent five (5) years. The exercise price per share of each of these Options shall be the fair market value of the Common Stock, as determined by the board of directors at the time the Options are grant. The specific terms and conditions of your Options will be subject to the terms of the 2007 Stock Plan, as well as the terms set forth in a Stock Option Agreement between you and the Company. This Stock Option Agreement will be entered into and executed after you commence your employment with the Company. In-addition to the foregoing, we anticipate that you will also be granted options to purchase a corresponding type and number of shares in each of the entities which the Company has previously spun-out as stand-alone entities (the “Related Entities”). The specific terms and conditions of the options in the Related Entities (the “Related Entity Options”) will be subject to the terms of the 2012 Stock Plan for each Related Entity, as well as the terms set forth in a Stock Option Agreement between you and the Related Entity. The vesting of the shares subject to the Options and Related Entity Options will be subject to acceleration in full if your employment with the Company is terminated by the Company (or any successor thereto) without Cause (as defined in the aTyr Plan) within twelve (12) months following a Change in Control (as defined in the aTyr Plan).

Relocation Assistance:

You will be offered a lump sum relocation assistance payment in the amount of $50,000.00 to be paid at the time of your first paycheck. This amount will be grossed up for tax purposes. This payment will be subject to repayment to the Company if you voluntarily resign within one year following commencing your employment.

Benefits:

You will be entitled to receive standard medical, life and dental insurance benefits for yourself and your dependents in accordance with Company policy. Company reserves the right to change or eliminate these benefits on a prospective basis at any time.

You will be eligible to participate in the aTyr Pharma, Inc. 401(k) Savings Plan immediately following the start of your employment.

You will be entitled to accrue 15 days of vacation per year. You will have 6 days of sick time available each year.

You will be eligible for aTyr’s paid holidays. The schedule is published prior to the beginning of each calendar year.

Your employment will be at-will, which means it may be terminated at any time by you or the Company for any reason, with or without cause, and that your employment is not for any specific period of time. Any change to the at-will employment relationship must be by a specific, written agreement signed by you and the Company’s Chief Executive Officer.

Start Date:

March 17, 2014 or a mutually agreed upon date.

/s/ David Weiner, M.D.

Date 2-21-14                                        

David Weiner, M.D.