I have never used MATLAB before, but from the documentation it looks like you can create a MATLAB class by targeting the wsdl of SharePoint's "Lists" web service. You can use the following URL to access the wsdl, replacing with the SharePoint site that contains the list you need to alter.
http:///_vti_bin/Lists.asmx?wsdl
References:
http://msdn.microsoft.com/en-us/library/Lists(v=office.12).aspx http://www.mathworks.com/help/matlab/matlab_external/accessing-web-services-that-use-wsdl-documents.html