I saw many post regarding this issue but non of them calling action support from apexgridPanel.
PageBlock have 2 coloumn but in one row I have to display two checkbox in one coloumn so I used gridPanel for this.
On click of check I have to hide and display one pageblock section. So On click of checkbox I am calling action hideDisplayLOB using
action support but actionsupport unable to hit action on controller.

Visualforce page(I can't provide full code) - 
<apex:pageBlockSectionItem id="uatSection">
                    <apex:outputLabel value="User Account Type" />
                    <apex:panelGrid columns="5" id="pg">
                        <apex:outputLabel value="Admin"/>
                        <apex:inputCheckbox id="admin" value="{!hsProvi.Admin__c}" disabled="{!isAdminDisable}" />                        
                         <apex:outputLabel value="User"/>
                         <apex:actionRegion>
                             <apex:inputCheckbox id="user" value="{!hsProvi.User__c}" disabled="{!isUserDisable}"/>
                             <apex:actionSupport  event="onclick" reRender="sslob" action="{!hideDisplayLOB}"></apex:actionSupport>
                         </apex:actionRegion>
                   </apex:panelGrid>                   
                </apex:pageBlockSectionItem> 
                   <apex:pageBlockSectionItem >
                    <apex:outputLabel value="Admin Role"/>
                    <!-- apex:outputLabel value="{!roleList}" /-->
                     <apex:selectList id="adminRole" value="{!roleName}" size="1" disabled="true">
                        <apex:selectOptions value="{!roleOptions}"/>
                    </apex:selectList>
                </apex:pageBlockSectionItem>
                <apex:pageBlockSectionItem id="ss" rendered="{!lobDisplay}">
                    <apex:outputPanel id="sslob">
                    <apex:outputLabel value="Line of Business"/>
                    <apex:inputField id="lob" value="{!hsProvi.HS_Line_of_Business__c}" />
                       </apex:outputPanel>
                </apex:pageBlockSectionItem>  

Cotroller
public pageReference hideDisplayLOB(){
         System.debug('Hide Dispaly LOB');
         if(hsProvi.User__c) {
             lobDisplay = true;
         }
         else {
             lobDisplay = false;
         }
         return null;
     }