SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of Report (Date of earliest event

Reported): May 30, 2007

J.P. MORGAN ACCEPTANCE CORPORATION I (as depositor under the Pooling and Servicing Agreement, relating to the J.P. Alternative Loan Trust 2007-S1, Mortgage Pass-Through Certificates, Series 2007-S1)


J.P. ALTERNATIVE LOAN TRUST 2007-S1
(Exact name of Issuing Entity as specified in its charter)

J.P. MORGAN ACCEPTANCE CORPORATION I
(Exact name of Depositor as specified in its charter)

J.P. MORGAN MORTGAGE ACQUISITION CORP.
(Exact name of Sponsor as specified in its charter)
Delaware	333-141607-05	13-3475488
(State or Other Jurisdiction of Incorporation)	(Commission File Number)	(I.R.S. Employer Identification No.)

270 Park Avenue New York, New York 10017
(Address of Principal Executive Offices) (Zip Code)

Registrant’s telephone number, including area code (212) 834-3850

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

[ ] Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

[ ] Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

[ ] Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

[ ] Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 8.01. Other Events.

McKee Nelson LLP has been retained by this Registrant as counsel for its Registration Statement on Form S-3 (Commission File No. 333-141607) in connection with various transactions. Legal opinions by McKee Nelson LLP to be incorporated into the Registration Statement are attached hereto as Exhibit 5.1, Exhibit 8.1 and Exhibit 23.1.

Item 9.01. Financial Statements and Exhibits

(a)

Not applicable.

(b)

Not applicable.

(c)

Not applicable.

(d)

Exhibits:

5.1

Opinion of McKee Nelson LLP as to legality (including consent of such firm).

8.1

Opinion of McKee Nelson LLP as to certain tax matters (including consent of such firm included in Exhibit 5.1).

23.1

Consent of McKee Nelson LLP (included in Exhibit 5.1).

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

J.P. MORGAN ACCEPTANCE CORPORATION I

By:/s/ Rosa Hyun

Name: Rosa Hyun

Title: Vice President

Dated: May 30, 2007

EXHIBIT INDEX

Exhibit No.

Description

5.1

Opinion of McKee Nelson LLP as to legality (including consent of such firm).

8.1

Opinion of McKee Nelson LLP as to certain tax matters (including consent of such firm included in Exhibit 5.1).

23.1

Consent of McKee Nelson LLP (included in Exhibit 5.1).

J.P. Morgan Alternative Loan Trust 2007-S1 8-K