<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2014-10-21</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001359931</issuerCik>
        <issuerName>PROTEON THERAPEUTICS INC</issuerName>
        <issuerTradingSymbol>PRTO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001324617</rptOwnerCik>
            <rptOwnerName>Skyline Venture Partners Qualified Purchaser Fund IV L P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>525 UNIVERSITY AVENUE, SUITE 610</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>PALO ALTO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94301</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001392103</rptOwnerCik>
            <rptOwnerName>Skyline Venture Management IV, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>525 UNIVERSITY AVENUE, SUITE 610</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>PALO ALTO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94301</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001296771</rptOwnerCik>
            <rptOwnerName>Freund John Gordon</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>525 UNIVERSITY AVENUE, SUITE 610</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>PALO ALTO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94301</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001277503</rptOwnerCik>
            <rptOwnerName>KANEKO YASUNORI</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>525 UNIVERSITY AVENUE, SUITE 610</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>PALO ALTO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94301</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Series A Convertible Preferred Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>5000000</value>
                    <footnoteId id="F1"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Series A-1 Convertible Preferred Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F3"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2341664</value>
                    <footnoteId id="F3"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Series B Convertible Preferred Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F4"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2173913</value>
                    <footnoteId id="F4"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Series C Convertible Preferred Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F5"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F5"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F5"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2436437</value>
                    <footnoteId id="F5"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Series D Convertible Preferred Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F6"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F6"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F6"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>3932747</value>
                    <footnoteId id="F6"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Option (Right to Purchase)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F7"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F7"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F7"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Series D Convertible Preferred Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1389064</value>
                    <footnoteId id="F6"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Warrants (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>4.6023</value>
                <footnoteId id="F9"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F8"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F8"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>121760</value>
                    <footnoteId id="F9"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The Series A Convertible Preferred Stock is convertible into the Issuer's Common Stock on an 1-for-1.19 basis without payment of further consideration and has no expiration date.  Each share will automatically convert into the Issuer's Common Stock concurrently with the completion of the Issuer's initial public offering of Common Stock. The shares do not reflect a 1-for-15.87 reverse stock split effected on October 6, 2014.</footnote>
        <footnote id="F2">The shares are held by Skyline Venture Partners Qualified Purchaser Fund IV L.P. (&quot;Skyline&quot;). John G. Freund, M.D. and Yasunori Kaneko, M.D. are Managing Directors of Skyline Venture Management IV, LLC, the sole general partner of Skyline, and may be deemed to share voting and dispositive power over the shares held by Skyline. Each of Drs. Freund and Kaneko disclaim beneficial ownership of such shares, except to the extent of their pecuniary interest therein.</footnote>
        <footnote id="F3">The Series A-1 Convertible Preferred Stock is convertible into the Issuer's Common Stock on a 1-for-1.22 basis without payment of further consideration and has no expiration date.  Each share will automatically convert into the Issuer's Common Stock concurrently with the completion of the Issuer's initial public offering of Common Stock. The shares do not reflect a 1-for-15.87 reverse stock split effected on October 6, 2014.</footnote>
        <footnote id="F4">The Series B Convertible Preferred Stock is convertible into the Issuer's Common Stock on a 1-for-1.23 basis without payment of further consideration and has no expiration date.  Each share will automatically convert into the Issuer's Common Stock concurrently with the completion of the Issuer's initial public offering of Common Stock. The shares do not reflect a 1-for-15.87 reverse stock split effected on October 6, 2014.</footnote>
        <footnote id="F5">The Series C Convertible Preferred Stock is convertible into the Issuer's Common Stock on a 1-for-1.23 basis without payment of further consideration and has no expiration date.  Each share will automatically convert into the Issuer's Common Stock concurrently with the completion of the Issuer's initial public offering of Common Stock. The shares do not reflect a 1-for-15.87 reverse stock split effected on October 6, 2014.</footnote>
        <footnote id="F6">The Series D Convertible Preferred Stock is convertible into the Issuer's Common Stock on a one-for-one basis without payment of further consideration and has no expiration date.  Each share will automatically convert into the Issuer's Common Stock concurrently with the completion of the Issuer's initial public offering of Common Stock. The shares do not reflect a 1-for-15.87 reverse stock split effected on October 6, 2014.</footnote>
        <footnote id="F7">Skyline has the right to purchase shares of Series D Convertible Preferred Stock under the Series D Purchase Agreement at a price of $0.588656, which right to purchase is not currently exercisable and shall terminate upon the completion of the Issuer's initial public offering of Common Stock.</footnote>
        <footnote id="F8">In connection with the Issuer's initial public offering of Common Stock, Skyline has irrevocably elected to exercise the warrants effective and contingent upon and immediately prior to the closing of the Issuer's initial public offering.  The warrants otherwise expire on an initial public offering, stock sale or deemed liquidation event.</footnote>
        <footnote id="F9">Reflects a 1-for-15.87 reverse stock split effected on October 6, 2014.</footnote>
    </footnotes>

    <remarks>Exhibit 24.1 Power of Attorney</remarks>

    <ownerSignature>
        <signatureName>/s/ Karensa Kenny as attorney-in-fact Skyline Venture Partners Qualified Purchaser Fund IV L.P.</signatureName>
        <signatureDate>2014-10-21</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Karensa Kenny as attorney-in-fact Skyline Venture Management IV, LLC</signatureName>
        <signatureDate>2014-10-21</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Karensa Kenny as attorney-in-fact John Gordon Freund</signatureName>
        <signatureDate>2014-10-21</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Karensa Kenny as attorney-in-fact Yasunori Kaneko</signatureName>
        <signatureDate>2014-10-21</signatureDate>
    </ownerSignature>
</ownershipDocument>
