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 *
Domain Partners VIII, L.P.
   2. Issuer Name and Ticker or Trading Symbol
Atara Biotherapeutics, Inc. [ATRA] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director __X__ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
(Last)
(First)
(Middle)
C/O DOMAIN ASSOCIATES, LLC, ONE PALMER SQUARE		 3. Date of Earliest Transaction (Month/Day/Year)
10/21/2014
(Street)

PRINCETON, NJ 08542		 4. If Amendment, Date Original Filed(Month/Day/Year)
 6. Individual or Joint/Group Filing(Check Applicable Line)
___ Form filed by One Reporting Person
_X_ 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 10/21/2014   C   1,893,383 A (3) 1,893,383 D (1) (2)  
Common Stock 10/21/2014   P   248,159 A $ 11 2,141,542 D (1) (2)  

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
Series A Preferred Stock (3) 10/21/2014   C     1,272,607   (3)   (3) Common Stock 1,272,607 $ 0 0 D (1) (2)  
Series B Preferred Stock (3) 10/21/2014   C     620,776   (3)   (3) Common Stock 620,776 $ 0 0 D (1) (2)  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
Domain Partners VIII, L.P.
C/O DOMAIN ASSOCIATES, LLC
ONE PALMER SQUARE
PRINCETON, NJ 08542		     X    
BLAIR JAMES C
C/O DOMAIN ASSOCIATES, LLC
ONE PALMER SQUARE
PRINCETON, NJ 08542		     X    
DOVEY BRIAN H
C/O DOMAIN ASSOCIATES, LLC
ONE PALMER SQUARE
PRINCETON, NJ 08542		     X    
TREU JESSE I
C/O DOMAIN ASSOCIATES, LLC
ONE PALMER SQUARE
PRINCETON, NJ 08542		     X    
SCHOEMAKER KATHLEEN K
C/O DOMAIN ASSOCIATES, LLC
ONE PALMER SQUARE
PRINCETON, NJ 08542		     X    
VITULLO NICOLE
C/O DOMAIN ASSOCIATES, LLC
ONE PALMER SQUARE
PRINCETON, NJ 08542		     X    
Halak Brian K
C/O DOMAIN ASSOCIATES, LLC
ONE PALMER SQUARE
PRINCETON, NJ 08542		     X    

Signatures

 /s/ Kathleen K. Schoemaker, as Managing Member of One Palmer Square Associates VIII, LLC, the general partner of Domain Partners VIII, L.P., individually and as Attorney-in-Fact for J. Blair, B. Dovey, J. Treu, N. Vitullo and B. Halak   10/21/2014
**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) The securities reported as directly beneficially owned by the designated Reporting Person may be deemed to be indirectly beneficially owned by each of the Reporting Owners listed below, each of whom is a managing member of One Palmer Square Associates VIII, LLC, the sole general partner of the designated Reporting Person. Pursuant to Instruction 4(b)(iv) of Form 4, each such individual has elected to report as indirectly beneficially owned the entire number of securities owned by the designated Reporting Person, however each of them disclaims beneficial ownership of any securities, and any proceeds thereof, that exceed his or her pecuniary interest therein and/or that are not actually distributed to him or her.
(2) As managing members of the sole general partner of DP VIII Associates, L.P., each Reporting Owner listed below may also be deemed to indirectly beneficially own the securities of the Issuer held by DP VIII Associates, L.P., as reported on a Form 4 for DP VIII Associates, L.P. filed on the same date as this Form 4.
(3) All outstanding shares of the Issuer's preferred stock automatically converted into Common Stock upon the closing of the Issuer's initial public offering for no additional consideration. The preferred stock had no expiration date.

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