SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF 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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1. Name and Address of Reporting Person* NODELMAN OLEG (Last) (First) (Middle) 357 TEHAMA STREET #3 (Street) SAN FRANCISCO CA 94103 (City) (State) (Zip)	2. Date of Event Requiring Statement (Month/Day/Year) 12/03/2019	3. Issuer Name and Ticker or Trading Symbol Prothena Corp plc [ PRTA ]
		4. Relationship of Reporting Person(s) to Issuer (Check all applicable) X Director X 10% Owner Officer (give title below) Other (specify below)	5. If Amendment, Date of 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

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Ordinary Shares	9,426,640	I	See Note(1)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Mr. Nodelman is the manager and controlling owner of EcoR1 Capital, LLC ("EcoR1"), an investment adviser to private investment funds (the "Funds"). The Funds hold these securities directly for the benefit of their investors, EcoR1 indirectly beneficially owns such securities as the investment adviser to the Funds, and Mr. Nodelman indirectly beneficially owns them as the control person of EcoR1. Mr. Nodelman disclaims beneficial ownership of such securities except to the extent of his pecuniary interest therein and disclaims membership in a group with the Funds within the meaning of Rule 13d-5(b) under the Securities Exchange Act of 1934, as amended.

	/s/ Oleg Nodelman	12/12/2019
	** 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 5 (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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