Sec Form 4 Filing - Ekman Lars @ PROTHENA CORP PUBLIC LTD CO - 2021-02-12

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 Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Ekman Lars 2. Issuer Name and Ticker or Trading Symbol PROTHENA CORP PUBLIC LTD CO [ PRTA] 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) C/O PROTHENA BIOSCIENCES INC, 331 OYSTER POINT BOULEVARD 3. Date of Earliest Transaction (MM/DD/YY) 02/12/2021 (Street) SOUTH SAN FRANCISCO, CA94080 4. If Amendment, Date Original Filed (MM/DD/YY) 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 (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 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 Employee Stock Option (Right to Buy) $ 34.04 02/12/2021 D 15,000 05/18/2016 05/22/2025 Ordinary Shares 15,000 ( 1 ) 0 D Employee Stock Option (Right to Buy) $ 22.85 02/12/2021 A 9,803 ( 2 ) 05/22/2025 Ordinary Shares 9,803 ( 1 ) 9,803 D Employee Stock Option (Right to Buy) $ 42.5 02/12/2021 D 15,000 05/16/2017 05/20/2026 Ordinary Shares 15,000 ( 3 ) 0 D Employee Stock Option (Right to Buy) $ 22.85 02/12/2021 A 8,426 ( 2 ) 05/20/2026 Ordinary Shares 8,426 ( 3 ) 8,426 D Employee Stock Option (Right to Buy) $ 56.23 02/12/2021 D 12,000 05/14/2018 05/18/2027 Ordinary Shares 12,000 ( 4 ) 0 D Employee Stock Option (Right to Buy) $ 22.85 02/12/2021 A 6,315 ( 2 ) 05/18/2027 Ordinary Shares 6,315 ( 4 ) 6,315 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Ekman Lars C/O PROTHENA BIOSCIENCES INC 331 OYSTER POINT BOULEVARD SOUTH SAN FRANCISCO, CA94080 X Signatures /s/ Michael J. Malecek, as Attorney in Fact for Lars G. Ekman 02/17/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )On February 12, 2021, the issuer canceled, pursuant to the issuer's option exchange program, an option for 15,000 of the issuer's ordinary shares granted to the reporting person on May 22, 2015. In exchange, the reporting person received a replacement option, for 9,803 ordinary shares, having an exercise price of $22.85 per ordinary share. ( 2 )The shares subject to the option will vest and become exercisable on the one year anniversary of the date of grant, subject to the reporting person's continued service with the issuer through such one year anniversary. ( 3 )On February 12, 2021, the issuer canceled, pursuant to the issuer's option exchange program, an option for 15,000 of the issuer's ordinary shares granted to the reporting person on May 20, 2016. In exchange, the reporting person received a replacement option, for 8,426 ordinary shares, having an exercise price of $22.85 per ordinary share. ( 4 )On February 12, 2021, the issuer canceled, pursuant to the issuer's option exchange program, an option for 12,000 of the issuer's ordinary shares granted to the reporting person on May 18, 2017. In exchange, the reporting person received a replacement option, for 6,315 ordinary shares, having an exercise price of $22.85 per ordinary share.

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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