Helping NATO for the US

Recently watching the news on television my niece asked me what is NATO...? I told her it means "North Atlantic treaty organization"she said okay...but after that I begin to think....
Pakistan is not a signatory to it like Albania ,Turkey and other 26 countries...(28 in all).
Pakistan is also not a partner country like ireland and russia or the NATO's Mediterranean Dialogue like Israel and Egypt Or

Istanbul cooperation Initiative(ici) like Bahrain and UAE
Pakistan is not even in the Contact countries like Australia and Japan...
So why is that every other day we hear a Pakistan-Nato related news on international media especially about the convoys being attacked or burned somewhere in a remote area of Pakistan on or near the border of Afghanistan.

Well so far what i have learned on a need to know basis is that US is at war in Afghanistan thousands of troops marines and air force is deployed across the landlocked country...and Pakistan happens to be in the neighborhood eager to make quick bucks out of anybody's misery....offered its already existing road network built probably by the US money in Aid over the years....not expecting or demanding any other privileges that other Nato countries hope for in order not to be obliged to abide by any  responsibility that the member countries have to...
So what happens now is that US and Nato supplies and JP-8 fuel is offloaded at Karachi Port by ships and then from here it goes all the way into Afghanistan through 18-wheelers which take couple of days.
Recently there have been too many arson attacks on these convoys carrying everything easily combustible...or flammable..so there is a growing concern on both sides of  this unholy alliance of a Non Nato Pakistan and Nato.
 If  Nato takes action in the Pakistani side of the border it violate Pakistan's sovereignty on the other hand if it does not save its convoys...it could be bad for the fighting troops.