<SEC-DOCUMENT>0001209191-18-031121.txt : 20180517
<SEC-HEADER>0001209191-18-031121.hdr.sgml : 20180517
<ACCEPTANCE-DATETIME>20180517174814
ACCESSION NUMBER:		0001209191-18-031121
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20180515
FILED AS OF DATE:		20180517
DATE AS OF CHANGE:		20180517

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Giraudo Bryan
		CENTRAL INDEX KEY:			0001740847

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-37852
		FILM NUMBER:		18844369

	MAIL ADDRESS:	
		STREET 1:		7707 GATEWAY BOULEVARD, SUITE 140
		CITY:			NEWARK
		STATE:			CA
		ZIP:			94560

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Protagonist Therapeutics, Inc
		CENTRAL INDEX KEY:			0001377121
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				980505495
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		7707 GATEWAY BLVD., SUITE 140
		CITY:			NEWARK
		STATE:			CA
		ZIP:			94560-1160
		BUSINESS PHONE:		(510) 474-0170

	MAIL ADDRESS:	
		STREET 1:		7707 GATEWAY BLVD., SUITE 140
		CITY:			NEWARK
		STATE:			CA
		ZIP:			94560-1160

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Protagonist Therapeutics Inc
		DATE OF NAME CHANGE:	20130605

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Protagonist Inc
		DATE OF NAME CHANGE:	20061002
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc4.xml
<DESCRIPTION>FORM 4 SUBMISSION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2018-05-15</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001377121</issuerCik>
        <issuerName>Protagonist Therapeutics, Inc</issuerName>
        <issuerTradingSymbol>PTGX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001740847</rptOwnerCik>
            <rptOwnerName>Giraudo Bryan</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>7707 GATEWAY BLVD., SUITE 140</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEWARK</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94560-1160</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2017-05-16</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>10000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>6.4566</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>6.45</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2018-05-15</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>24000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2028-05-14</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>24000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>24000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The price reported in Column 4 is a weighted average price.  These shares were purchased in multiple transactions at prices ranging from $6.43 to $6.50, inclusive.  The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the Staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range.</footnote>
        <footnote id="F2">The shares subject to the option shall vest in 36 equal monthly installments from the vesting commencement date of May 15, 2018.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Thomas P. O'Neil, Attorney-in-Fact</signatureName>
        <signatureDate>2018-05-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
