MATLAB to Arduino to GSM

I want to transfer control to Arduino from MATLAB so that it can signal an alarm in the form of an SMS through a GSM module. Like, if a certain condition is met in my MATLAB code, Arduino can take over and do the needful.

I am done with the interfacing of Arduino with GSM and am able to send an SMS.

But I am stuck with the portion of transferring control to Arduino from MATLAB.

Please help.
Thank you.

There is no need to transfer control.

Have Matlab tell the Arduino what to do. Simple.

Thank you for replying. Do you mean to say that all I need to do is write a script for interfacing MATLAB with Arduino?