ASSIGNMENT, ASSUMPTION AND RECOGNITION AGREEMENT

Execution Copy

ASSIGNMENT, ASSUMPTION AND RECOGNITION AGREEMENT

THIS ASSIGNMENT, ASSUMPTION AND RECOGNITION AGREEMENT (this “Assignment”), dated as of December 1, 2006, is entered into among J.P. Morgan Acceptance Corporation I, a Delaware corporation (the “Depositor”), U.S. Bank National Association, as trustee (the “Trustee”) of J.P. Morgan Mortgage Trust 2006-S4 (the “Trust”), J.P. Morgan Mortgage Acquisition Corp. (“JPMorgan Acquisition”), JPMorgan Chase Bank, National Association (“JPMCBNA”), Chase Home Finance LLC (“CHF”) and Wells Fargo Bank, N.A. (the “Master Servicer”).

RECITALS

WHEREAS JPMorgan Acquisition, CHF and JPMCBNA have entered into a certain Flow Mortgage Loan Purchase, Warranties and Servicing Agreement, dated as of May 1, 2004 (the “Purchase Agreement”), as amended by Amendment No. 1 thereto, dated as of January 1, 2005 (the “Amendment No. 1”), as amended by Amendment No. 2 thereto, dated as of December 1, 2005 (the “Amendment No. 2”) and as further amended by that certain Amendment Reg AB, dated as of January 1, 2006, (the “Amendment Reg AB” and together with the Purchase Agreement, Amendment No. 1 and Amendment No. 2, the “Agreement”), pursuant to which JPMorgan Acquisition has acquired certain Mortgage Loans pursuant to the terms of the Agreement and JPMCBNA has agreed to service such Mortgage Loans;

WHEREAS the Depositor has agreed, on the terms and conditions contained herein, to purchase from JPMorgan Acquisition certain of the Mortgage Loans (the “Specified Mortgage Loans”) which are subject to the provisions of the Agreement and are listed on the mortgage loan schedule attached as Exhibit I hereto (the “Specified Mortgage Loan Schedule”);

WHEREAS, pursuant to the Agreement, JPMCBNA has agreed to service the Specified Mortgage Loans for a Servicing Fee Rate of 0.25%; and

WHEREAS the Trustee, on behalf of the Trust, has agreed, on the terms and conditions contained herein, to purchase from the Depositor the Specified Mortgage Loans;

NOW, THEREFORE, in consideration of the mutual promises contained herein and other good and valuable consideration (the receipt and sufficiency of which are hereby acknowledged), the parties agree as follows:

1.

Assignment and Assumption

(a)

On and as of the date hereof, JPMorgan Acquisition hereby sells, assigns and transfers to the Depositor all of its right, title and interest in the Specified Mortgage Loans and all rights and obligations related thereto as provided under the Agreement to the extent relating to the Specified Mortgage Loans, the Depositor hereby accepts such assignment from JPMorgan Acquisition  (the “First Assignment and Assumption”), and CHF and JPMCBNA hereby acknowledge the First Assignment and Assumption.

JPMorgan Acquisition specifically reserves and does not assign to the Depositor hereunder any and all right, title and interest in, to and under and all obligations of JPMorgan Acquisition with respect to any Mortgage Loans subject to the Agreement which are not the Specified Mortgage Loans.

(b)

On and as of the date hereof, immediately after giving effect to the First Assignment and Assumption, the Depositor hereby sells, assigns and transfers to the Trustee, on behalf of the Trust, all of its right, title and interest in the Specified Mortgage Loans and all rights and obligations related thereto as provided under the Agreement to the extent relating to the Specified Mortgage Loans, and the Trustee, on behalf of the Trust, hereby accepts such assignment from the Depositor (the “Second Assignment and Assumption”), and CHF and JPMCBNA hereby acknowledge the Second Assignment and Assumption.

(c)

On and as of the date hereof, JPMorgan Acquisition represents and warrants to the Depositor and the Trustee that JPMorgan Acquisition has not taken any action that would serve to impair or encumber the respective ownership interests of the Depositor and the Trustee in the Specified Mortgage Loans since the date of JPMorgan Acquisitions’ acquisition of the Specified Mortgage Loans.

2.

Recognition of Trustee

(a)

From and after the date hereof, each of JPMorgan Acquisition, CHF and JPMCBNA shall note the transfer of the Specified Mortgage Loans to the Trustee, in their respective books and records and shall recognize the Trustee, on behalf of the Trust, as of the date hereof, as the owner of the Specified Mortgage Loans, and JPMCBNA shall service the Specified Mortgage Loans for the benefit of the Trust pursuant to the Agreement, the terms of which are incorporated herein by reference. It is the intention of JPMCBNA, the Depositor, the Trustee and JPMorgan Acquisition that this Assignment shall be binding upon and inure to the benefit of the Depositor, the Trustee and JPMorgan Acquisition and their respective successors and assigns.

(b)

Without in any way limiting the foregoing, the parties confirm that this Assignment includes the rights relating to amendments under the Agreement.  Accordingly, the right of JPMorgan Acquisition to consent to any amendment of the Agreement as set forth in Section 12.02 of the Agreement shall be exercisable, to the extent any such amendment affects the Specified Mortgage Loans or any of the rights or obligations under the Agreement with respect thereto (including, without limitation, the servicing of the Specified Mortgage Loans), by the Trustee as assignee of JPMorgan Acquisition.

3.

Representations and Warranties

(a)

The Depositor represents and warrants that it is a sophisticated investor able to evaluate the risks and merits of the transactions contemplated hereby, and that it has not relied in connection therewith upon any statements or representations of CHF, JPMCBNA or JPMorgan Acquisition other than those contained in the Agreement or this Assignment.

(b)

Each of the parties hereto represents and warrants that it is duly and legally authorized to enter into this Assignment.

(c)

Each of the parties hereto represents and warrants that this Assignment has been duly authorized, executed and delivered by it and (assuming due authorization, execution and delivery thereof by each of the other parties hereto) constitutes its legal, valid and binding obligation, enforceable against it in accordance with its terms, except as such enforcement may be limited by bankruptcy, insolvency, reorganization or other similar laws affecting the enforcement of creditors’ rights generally and by general equitable principles (regardless of whether such enforcement is considered in a proceeding in equity or at law).

4.

JPMCBNA hereby acknowledges that Wells Fargo Bank, N.A. has been appointed as the Master Servicer of the Specified Mortgage Loans pursuant to the pooling and servicing agreement dated as of the date hereof among the Depositor, the Master Servicer, the Securities Administrator and the Trustee  (the “Pooling and Servicing Agreement”) for Mortgage Pass-Through Certificates, Series 2006-S4 and, therefore, has the right to enforce all obligations of JPMCBNA under the Agreement. Such rights will include, without limitation, the right to terminate JPMCBNA under the Agreement upon the occurrence of an event of default thereunder, the right to receive all remittances required to be made by JPMCBNA under the Agreement, the right to receive all monthly reports and other data required to be delivered by JPMCBNA under the Agreement, the right to examine the books and records of JPMCBNA relating to the Mortgage Loans, indemnification rights and the right to exercise certain rights of consent and approval relating to actions taken by JPMorgan Acquisition. JPMCBNA shall make all distributions under the Agreement to the Master Servicer by wire transfer of immediately available funds to:

Wells Fargo Bank, N.A.

ABA Number:

121-000-248

Account Name:  SAS Clearing

Account number:  3970771416

For further credit to:  J.P. Morgan Mortgage Trust 2006-S4,

        Distribution Account Number: 50972700

JPMCBNA shall deliver all reports required to be delivered under the Agreement to the Master Servicer at the following address:

Wells Fargo Bank, N.A.

9062 Old Annapolis Road

Columbia, Maryland 21045

Attention: Client Manager – JPMMT 2006-S4

Telecopier: (410) 715-2380

5.

Subservicing Agreement

As of the Closing Date (as defined in the Pooling and Servicing Agreement) JPMCBNA has engaged CHF to act as subservicer with respect to JPMCBNA’s servicing obligations under the Agreement. So long as JPMCBNA is not a rated servicer by Standard and Poor’s, JPMCBNA agrees that prior to replacing CHF as subservicer, other than with an affiliate of JPMCBNA that is a rated servicer, it will obtain written confirmation from Standard & Poor's, a division of The McGraw-Hill Companies, Inc. (“Standard & Poor’s”), that such replacement of CHF as subservicer with respect to JPMCBNA’s servicing obligations related to the Mortgage Loans will not cause the current rating on t