Statement of Changes in Beneficial Ownership (4)

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	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response... 0.5
	Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

1. Name and Address of Reporting Person * Nashat Amir	2. Issuer Name and Ticker or Trading Symbol Receptos, Inc. [ RCPT ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __ X __ Director                      _____ 10% Owner _____ Officer (give title below)      _____ Other (specify below)
(Last)          (First)          (Middle) 10835 ROAD TO THE CURE, SUITE 205	3. Date of Earliest Transaction (MM/DD/YYYY) 5/14/2013
(Street) SAN DIEGO, CA 92121 (City)        (State)        (Zip)	4. If Amendment, Date Original Filed (MM/DD/YYYY)	6. Individual or Joint/Group Filing (Check Applicable Line) _ X _ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security (Instr. 3)	2. Trans. Date	2A. Deemed Execution Date, if any	3. Trans. 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	5/14/2013		C		1035597	A	$7.73	1035597	I	See Footnotes   (1) (2)
Common Stock	5/14/2013		P		151343	A	$14.00	1186940	I	See Footnotes   (1) (2)

Table II - Derivative Securities Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities)
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	4. Trans. 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		7. Title and Amount of Securities Underlying Derivative Security (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 B Preferred Stock	$7.73	5/14/2013		C   (3)			7766989	(3)	(3)	Common Stock	1035597	$0	0	I	See Footnotes   (1) (2)

Explanation of Responses:
( 1)	Beneficial ownership consists of; (i) 142,764 shares of common stock held by Polaris Venture Partners VI, L.P. ("Polaris Ventures"); (ii) 8,579 shares of common stock held by Polaris Venture Partners Founders' Fund VI, L.P. ("Polaris Fund"); (iii) an aggregate of 976,897 shares of common stock issued upon conversion of shares of Series B preferred stock held by Polaris Ventures; and (iv) an aggregate of 58,700 shares of common stock issued upon conversion of Series B preferred stock held by Polaris Fund. The general partner of Polaris Ventures and Polaris Fund is Polaris Venture Management Co. VI, LLC ("Polaris Management"), and Polaris Management has sole voting and investment power over such shares. Polaris Management disclaims beneficial ownership of all such shares, except to the extent of any pecuniary interest therein. Dr. Nashat is one of six members of Polaris Management.
( 2)	He has shared voting and investment power over such shares and may be deemed the indirect beneficial owner of such shares. Dr. Nashat disclaims beneficial ownership over such shares, except to the extent of any pecuniary interest therein. The members of North Star Venture Management 2010 LLC are also members of Polaris Management, and as members of the general partner, they may be deemed to share voting and investment power over such shares. The principles of North Star Venture Management 2010 LLC disclaim beneficial ownership of such shares, except to the extent of their proportionate pecuniary interest therein.
( 3)	The Series A Preferred Stock converted upon the closing of the Issuer's initial public offering at a conversion ratio of 1 share of Common Stock for every 7.5 shares of Series A Preferred Stock, for no additional consideration.

Reporting Owners
Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Nashat Amir 10835 ROAD TO THE CURE, SUITE 205 SAN DIEGO, CA 92121	X

Signatures
/s/ Amir Nashat		5/14/2013
** Signature of Reporting Person		Date

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
*	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).
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