X0306 4 2022-10-05 0 0001559053 PROTHENA CORP PUBLIC LTD CO PRTA 0001110751 COLLIER RICHARD T C/O PROTHENA BIOSCIENCES INC 331 OYSTER POINT BOULEVARD SOUTH SAN FRANCISCO CA 94080 1 0 0 0 Ordinary Shares, par value $0.01 per share 2022-10-05 4 M 0 5000 6.41 A 6219 D Ordinary Shares, par value $0.01 per share 2022-10-05 4 S 0 890 56.538 D 5329 D Ordinary Shares, par value $0.01 per share 2022-10-05 4 S 0 3404 57.9711 D 1925 D Ordinary Shares, par value $0.01 per share 2022-10-05 4 S 0 352 58.9418 D 1573 D Ordinary Shares, par value $0.01 per share 2022-10-05 4 S 0 354 59.9486 D 1219 D Stock Option (Right to Buy) 6.41 2022-10-05 4 M 0 5000 0 A 2014-01-29 2023-01-29 Ordinary Shares 5000 15000 D The transactions reported in the Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person. The transaction was executed in multiple trades in prices ranging from $56.37 to $56.87, inclusive. The price reported in Column 4 above reflects the weighted average sale price. The reporting person hereby undertakes to provide to the Securities and Exchange Commission staff, the Issuer, or a security holder of the Issuer, upon request, full information regarding the number of shares sold at each respective price within the ranges set forth in footnotes 2 through 5 of this Form 4. The transaction was executed in multiple trades in prices ranging from $57.53 to $58.48, inclusive. The transaction was executed in multiple trades in prices ranging from $58.585 to $59.30, inclusive. The transaction was executed in multiple trades in prices ranging from $59.90 to $60.00, inclusive. The option was granted on January 29, 2013, and all shares subject to the option were fully vested and exercisable January 29, 2014. The option will expire in approximately four months and be forfeited to the extent it is not exercised on or prior to January 29, 2023. /s/ Michael Malecek, as Attorney in Fact for Richard T. Collier 2022-10-07