FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
Ciechanover Isaac E.
   2. Issuer Name and Ticker or Trading Symbol
Atara Biotherapeutics, Inc. [ATRA] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Chief Executive Officer
(Last)
(First)
(Middle)
701 GATEWAY BOULEVARD, SUITE 200		 3. Date of Earliest Transaction (Month/Day/Year)
08/27/2015
(Street)

SOUTH SAN FRANCISCO, CA 94080		 4. If Amendment, Date Original Filed(Month/Day/Year)
 6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)		 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)		 4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)		 5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)		 6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)		 7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Stock 08/27/2015   S(1)   1,500 D $ 38.15 (2) 378,682 I See Footnote (3)
Common Stock 08/27/2015   S(1)   500 D $ 39.44 (4) 378,182 I See Footnote (3)
Common Stock 08/27/2015   S(1)   600 D $ 40.44 (5) 377,582 I See Footnote (3)
Common Stock 08/28/2015   S(1)   1,500 D $ 39.2 (6) 376,082 I See Footnote (3)
Common Stock 08/28/2015   S(1)   1,100 D $ 40.07 (7) 374,982 I See Footnote (3)
Common Stock               488,653 I See Footnote (8)
Common Stock               180,000 I See Footnote (9)
Common Stock               41,532 D  

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)		 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)		 5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)		 6. Date Exercisable and Expiration Date
(Month/Day/Year)		 7. Title and Amount of Underlying Securities
(Instr. 3 and 4)		 8. Price of Derivative Security
(Instr. 5)		 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)		 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)		 11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
Ciechanover Isaac E.
701 GATEWAY BOULEVARD
SUITE 200
SOUTH SAN FRANCISCO, CA 94080		   X     Chief Executive Officer  

Signatures

 /s/ Tina Gullotta, Attorney-in-Fact for Isaac E. Ciechanover   08/31/2015
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) Transaction pursuant to Rule 10b5-1 Plan adopted December 12, 2014.
(2) The price in Column 4 is a weighted average sale price. The prices actually received ranged from $37.77 to $38.67. The reporting person will provide to the issuer, any security holder of the issuer, or the SEC staff, upon request, information regarding the number of shares sold at each price within the range.
(3) Shares are held by the Isaac E. Ciechanover and Allison M. Ciechanover Family Trust dated 8/8/08, of which the Reporting Person is a trustee.
(4) The price in Column 4 is a weighted average sale price. The prices actually received ranged from $39.00 to $39.78. The reporting person will provide to the issuer, any security holder of the issuer, or the SEC staff, upon request, information regarding the number of shares sold at each price within the range.
(5) The price in Column 4 is a weighted average sale price. The prices actually received ranged from $40.275 to $40.57. The reporting person will provide to the issuer, any security holder of the issuer, or the SEC staff, upon request, information regarding the number of shares sold at each price within the range.
(6) The price in Column 4 is a weighted average sale price. The prices actually received ranged from $38.91 to $39.55. The reporting person will provide to the issuer, any security holder of the issuer, or the SEC staff, upon request, information regarding the number of shares sold at each price within the range.
(7) The price in Column 4 is a weighted average sale price. The prices actually received ranged from $39.98 to $40.17. The reporting person will provide to the issuer, any security holder of the issuer, or the SEC staff, upon request, information regarding the number of shares sold at each price within the range.
(8) Sheld are held by the Ciechanover Family GRAT, of which the Reporting Person is a trustee.
(9) Sheld are held by the The Ciechanover 2015 GRAT, of which the Reporting Person is a trustee.

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