ASSIGNMENT, ASSUMPTION AND RECOGNITION AGREEMENT

EXECUTION COPY

ASSIGNMENT, ASSUMPTION AND RECOGNITION AGREEMENT

THIS ASSIGNMENT, ASSUMPTION AND RECOGNITION AGREEMENT (this “ Agreement ”), dated as of October 27, 2006, among UBS Real Estate Securities Inc. (the “ Assignor ”), Mortgage Asset Securitization Transactions, Inc. (the “ Assignee ”), and SunTrust Mortgage, Inc. (the “ Company ” or “ Seller ”):

WHEREAS, the Company is currently servicing the mortgage loans identified on Exhibit A attached hereto (the “ Mortgage Loans ”) for the Assignor pursuant to a certain Seller’s, Purchase, Warranties and Servicing Agreement, dated as of November 1, 2005, as amended by the Regulation AB Compliance Addendum, dated as of September 1, 2006 (the “ Purchase Agreement ”); and

WHEREAS, the Assignor, the Assignee and the Company desire that, from and after the date hereof, (i) the Mortgage Loans be serviced in accordance with the terms and conditions of that certain Amended and Restated Purchase, Warranties and Servicing Agreement dated as of December 1, 2004, as amended by Amendment Number One, dated as of July 1, 2005, as further amended by Amendment Number Two, dated as of February 28, 2006, and as further amended by Amendment Number Three, dated as of April 1, 2006, (together, the “ Servicing Agreement ”) each between the Assignor and the Company, a copy of each of which is attached hereto as Exhibit B and (ii) the Servicing Agreement shall replace the Purchase Agreement pursuant to which the Company is currently servicing the Mortgage Loans.

For good and valuable consideration the receipt and sufficiency of which hereby are acknowledged, and of the promises and mutual covenants herein contained, the parties hereto hereby agree as follows:

1.

a.

The Assignor hereby conveys, sells, grants, transfers and assigns to the Assignee all of the right, title and interest (other than those rights specifically retained by the Assignor pursuant to this Agreement) of the Assignor, in, to and under (a) the Mortgage Loans and (b) solely with respect to the servicing provisions as they relate to the Mortgage Loans (as limited in Section 1(c) below), the Servicing Agreement.

b.

The Assignor specifically reserves and does not assign to the Assignee hereunder any and all right, title and interest in, to and under and all obligations of the Assignor with respect to any mortgage loans subject to the Servicing Agreement which are not the Mortgage Loans set forth on Exhibit A attached hereto and are not the subject of this Agreement.

c.

The Assignor specifically reserves and does not assign to the Assignee hereunder those rights under the Servicing Agreement that do not relate to the servicing of the Mortgage Loans (including without limitation, the representations and warranties made by the Company and the document delivery requirements of the Company and the remedies (including indemnification) available for breaches thereof).

2.

The Company warrants and represents to, and covenants with, the Assignor and the Assignee as of the date hereof:

a.

The Company hereby restates as of the date hereof for the benefit of the Assignee all the representations and warranties in Section 3.01 of the Servicing Agreement and with respect to Section 3.02 of the Servicing Agreement, those representations and warranties that pertain to the continuing obligations of the Company, as Servicer (as defined in the Servicing Agreement), with the same effect under such Servicing Agreement as if such representations and warranties had been made as of the date hereof;

b.

The Company hereby acknowledges and agrees that the remedies available to the Assignor, the Assignee and the Trustee in connection with any breach of the representations and warranties made by the Company set forth in this Agreement shall be as set forth in Section 3.03 of the Servicing Agreement as if they were set forth herein (including without limitation the repurchase and indemnity obligations set forth therein);

c.

The Company is duly organized, validly existing and in good standing under the laws of the jurisdiction of its incorporation, and has all requisite power and authority to service the Mortgage Loans and otherwise to perform its obligations under this Agreement;

d.

The Company has full corporate power and authority to execute, deliver and perform its obligations under this Agreement, and has full power and authority to perform its obligations under this Agreement.  The execution by the Company of this Agreement is in the ordinary course of the Company’s business and will not conflict with, or result in a breach of, any of the terms, conditions or provisions of the Company’s charter or bylaws or any legal restriction, or any material agreement or instrument to which the Company is now a party or by which it is bound, or result in the violation of any law, rule, regulation, order, judgment or decree to which the Company or its property is subject.  The execution, delivery and performance by the Company of this Agreement has been duly authorized by all necessary corporate action on part of the Company.  This Agreement has been duly executed and delivered by the Company, and, upon the due authorization, execution and delivery by the Assignor and the Assignee, will constitute the valid and legally binding obligation of the Company, enforceable against the Company in accordance with its terms except as enforceability may be limited by bankruptcy, reorganization, insolvency, moratorium or other similar laws now or hereafter in effect relating to creditors’ rights generally, and by general principles of equity regardless of whether enforceability is considered in a proceeding in equity or at law;

e.

No consent, approval, order or authorization of, or declaration, filing or registration with, any governmental entity is required to be obtained or made by the Company in connection with the execution, delivery or performance by the Company of this Agreement, or the consummation by it of the transactions contemplated hereby;

f.

There is no action, suit, proceeding or investigation pending or threatened against the Company, before any court, administrative agency or other tribunal, which would draw into question the validity of this Agreement or the Servicing Agreement, or which, either in any one instance or in the aggregate, would result in any material adverse change in the ability of the Company to perform its obligations under this Agreement or the Servicing Agreement.  The Company is solvent; and

g.

If any Mortgage has been recorded in the name of Mortgage Electronic Registration System, Inc. (“ MERS ”) or its designee, the Company shall take all actions as are necessary to cause MASTR Asset Securitization Trust 2006-3 to be shown as the owner of the related Mortgage Loan on the record of MERS for the purpose of the system of recording transfers of beneficial ownership of mortgage maintained by MERS.

Recognition by the Company of the Trustee and the Trust Administrator

3.

The Company hereby recognizes that the Mortgage Loans will be transferred by the Assignee to U.S. Bank National Association, as Trustee for the holders of MASTR Asset Securitization Trust 2006-3 (including its successors in interest and any successor trustee under the Pooling Agreement defined below, the “ Trustee ”) in a securitization transaction pursuant to a Pooling and Servicing Agreement, dated as of October 1, 2006 (the “ Pooling Agreement ”), among the Assignee, the Assignor, the Trustee and Wells Fargo Bank, N.A., as master servicer (the “ Master Servicer ”), trust administrator (the “ Trust Administrator ”) and as custodian.  From and after the date hereof, the Company acknowledges and agrees that (A) the Trustee will be the owner of the Mortgage Loans on behalf of MASTR Asset Securitization Trust 2006-3 (the “ Trust ”), and Wells Fargo Bank, N.A., will be the Master Servicer, Trust Administrator and custodian of the Mortgage Loans, (B) the Company shall look solely to the Trustee and the Trust Administrator, on behalf of the Trust, for performance of any obligations of the Assignor insofar as they relate to the Mortgage Loans and (C) the Mortgage Loans will be part of a “real estate mortgage investment conduit” within the meaning of Section 860D of the Code (“ REMIC ”), and the Company shall service the Mortgage Loans and any real property acquired upon default thereof (including, without limitation, making or permitting any modification, waiver or amendment of any term of any Mortgage Loan) in accordance with the Servicing Agreement but in no event in a manner that would (i) cause the REMIC to fail to qualify as a REMIC or (ii) result in the imposition of a tax upon the REMIC (including but not limited to the tax on prohibited transactions as defined in Section 860F(a)(2) of the Code, the tax on contributions to a REMIC set forth in Section 860G(d) of the Code, and the tax on “net income from foreclosure property” as set forth in Section 860G(c) of the Code).  It is the intention of the Assignor, the Company and the Assignee that this Agreement shall be binding upon and for the benefit of the respective successors and assigns of the parties hereto. Neither the Company nor the Assignor shall amend or agree to amend, modify, waive, or otherwise alter any of the terms or provisions of the Servicing Agreement which amendment, modification, waiver or other alteration would in any way affect the Mortgage Loans without the prior written consent of the Trustee.

Modification of the Servicing Agreement

4.

Only insofar as it relates to the Mortgage Loans, the parties hereto hereby amend the Servicing Agreement as follows:

(i)

The following paragraph is added immediately following the last paragraph of Section 4.04:

“Custodial Accounts shall be Eligible Accounts and funds on deposit in the Custodial Account shall only be invested in Permitted Investments.”  

(ii)

The definition of “Eligible Account” is hereby deleted in its entirety and replaced by the following:

Eligible Account :  Any of (i) an account or accounts maintained with a federal or state chartered depository institution or trust company the short term unsecured debt obligations of which (or, in the case of a depository institution or trust company that is the principal subsidiary of a holding company, the debt obligations of such holding company) have the highest short term ratings of each Rating Agency at the time any amounts are held on deposit therein, or (ii) an account or accounts in a depository institution or trust company in which such accounts are insured by the FDIC (to the limits established by the FDIC) and the uninsured deposits in which accounts are otherwise secured such that, as evidenced by an Opinion of Counsel delivered to the trustee, the trust administrator and to each Rating Agency, the certificateholders have a claim with respect to the funds in such account or a perfected first priority security interest against any collateral (which shall be limited to Permitted Investments) securing such funds that is superior to claims of any other depositors or creditors of the depository institution or trust company in which such account is maintained, or (iii) a non interest bearing segregated trust account or accounts maintained with (a) the trust department of a federal or state chartered depository institution or (b) a trust company, acting in its fiduciary capacity or (iv) any other account acceptable to each Rating Agency.  Eligible Accounts may bear interest, and may include, if otherwise qualified under this definition, accounts maintained with the Trustee.

 (iii)

The following definition is added to Section 1.01 of the Servicing Agreement immediately following the definition of “OTS”:

Permitted Investments :  At any time, any one or more of the following obligations and securities:

(a)

obligations of the United States or any agency thereof, provided such obligations are backed by the full faith and credit of the United States;

(b)

general obligations of or obligations guaranteed by any state of the United States or the District of Columbia receiving the highest long-term debt rating of each Rating Agency, or such lower rating as will not result in the downgrading or withdrawal of the ratings then assigned to the Certificates by either Rating Agency;

(c)

commercial or finance company paper which is then receiving the highest commercial or finance company paper rating of each Rating Agency, or such lower rating as will not result in the downgrading or withdrawal of the ratings then assigned to the Certificates by either Rating Agency;

(d)

certificates of deposit, demand or time deposits, or bankers’ acceptances issued by any depository institution or trust company incorporated under the laws of the United States or of any state thereof and subject to supervision and examination by federal and/or state banking authorities, provided that the commercial paper and/or long term unsecured debt obligations of such depository institution or trust company are then rated in one of the two highest long-term and the highest short-term ratings of each Rating Agency for such securities, or such lower ratings as will not result in the downgrading or withdrawal of the rating then assigned to the Certificates by either Rating Agency;

(e)

demand or time deposits or certificates of deposit issued by any bank or trust company or savings institution to the extent that such deposits are fully insured by the FDIC and are then rated in the highest long-term and the highest short-term ratings of each Rating Agency for such securities, or such lower ratings as will not result in the downgrading or withdrawal of the ratings then assigned to the Certificates by either Rating Agency;

(f)

guaranteed reinvestment agreements issued by any bank, insurance company or other corporation containing, at the time of the issuance of such agreements, such terms and conditions as will not result in the downgrading or withdrawal of the rating then assigned to the Certificates by either Rating Agency;

(g)

repurchase obligations with respect to any security described in clauses (a) and (b) above, in either case entered into with a depository institution or trust company (acting as principal) described in clause (d) above;

(h)

securities (other than stripped bonds, stripped coupons or instruments sold at a purchase price in excess of 115% of the face amount thereof) bearing interest or sold at a discount issued by any corporation incorporated under the laws of the United States or any state thereof which, at the time of such investment, have the highest rating of each Rating Agency, or such lower rating as will not result in the downgrading or withdrawal of the rating then assigned to the Certificates by either Rating Agency, as evidenced by a signed writing delivered by each Rating Agency;

(i)

units of a taxable money-market portfolio having the highest rating assigned by each Rating Agency and restricted to obligations issued or guaranteed by the United States of America or entities whose obligations are backed by the full faith and credit of the United States of America and repurchase agreements collateralized by such obligations;

(j)

any mutual fund, money market fund, common trust fund or other pooled investment vehicle, the assets of which are limited to instruments that otherwise would constitute Permitted Investments hereunder, including any such fund that is managed by the Trustee or Master Servicer or any affiliate of the Trustee or Master Servicer or for which the Trustee or Master Servicer or any affiliate of the Trustee or Master Servicer acts as an adviser as long as such fund is rated in at least the highest rating category by each Rating Agency (if so rated by such Rating Agency); and

(k)

such other investments bearing interest or sold at a discount acceptable to each Rating Agency as will not result in the downgrading or withdrawal of the rating then assigned to the Certificates by either Rating Agency, as evidenced by a signed writing delivered by each Rating Agency;

provided that no such instrument shall be a Permitted Investment if such instrument evidences the right to receive interest only payments with respect to the obligations underlying such instrument.

(iv)

Section 5.02 (“Statements to the Purchaser”) is hereby deleted in its entirety and replaced by the following:

Not later than the fifth (5th) Business Day of each month, the Seller shall furnish to the Purchaser or its designee a delinquency report in the form set forth in Exhibit L-1, a monthly remittance advice in the form set forth in Exhibit L-2, and a realized loss report in the form set forth in Exhibit L-3, each in a mutually agreeable electronic format, as to the latest Due Period, together with such other information with respect to the Mortgage Loans as the Purchaser may reasonably require to allocate distributions made pursuant to this Agreement and to provide appropriate statements in connection therewith.

The Seller shall prepare and file any and all information statements or other filings required to be delivered to any governmental taxing authority or to the Purchaser pursuant to any applicable law with respect to the Mortgage Loans and the transactions contemplated hereby. In addition, the Seller shall provide the Purchaser with such information concerning the Mortgage Loans as is necessary for the Purchaser to prepare its federal income tax return as the Purchaser may reasonably request from time to time.

In addition, not more than sixty (60) days after the end of each calendar year, the Seller shall furnish to each Person who was a Purchaser at any time during such calendar year an annual statement in accordance with the requirements of applicable federal income tax law as to the aggregate of remittances for the applicable portion of such year.

(v)

An Exhibit L to the Servicing Agreement is hereby added immediately following Exhibit K, substanti