[TYPO3-mvc] Class ActionController not found

[B L Praveen]

Build the extension using  a extension builder 2.5.2.
And I have used the vendor name as Cybrain. 
namespace Cybrain\MyExtension\Controller;

class MyController extends \typo3\sysext\extbase\Classes\Mvc\Controller\ActionController {}

But I am getting fatal error
 Class 'typo3\sysext\extbase\Classes\Mvc\Controller\MyController ' not found in /home/user/public_html/typo/typo3conf/ext/MyExtension/Classes/Controller/MyController .php on line 35

When I remove the namespace and my class
class MyController extends Tx_Extbase_MVC_Controller_ActionController

I get   error that ----->class not autoloaded 

I have created the exot_autoload file

$extensionClassesPath = t3lib_extMgm::extPath('MyExtension') . 'Classes/';
'auctioncontroller' => $extensionClassesPath . 'Controller/MyController .php',

I am not understanding proper conventions and formats used to in typo3, like namespace..

I am finding it hard to make my new extension  work .. 

If once this extension shows something I can start working on the project and play around with it. to understand