正在啃一门USP的课Brain and Cognition，问题是：

What two functions do proteins in the neural membrane serve to establish and maintain the resting membrane potential?

除了那个著名的Na-K Pump，还有另一个protein function是什么呢？是不是其他protein channels, the Na+ or K+ or Ca2+ gates统统并在一类里算是另一个function carried out by proteins?

但书上没有这样子划分的...向专业的筒子请教——谢谢~~~

no need to classify, all ion channel function is one.

I am not sure about the other. To keep the membrane integrity?

Maybe Na-K ATPase and Cl channel?

Really confused of your question.

Ion channels是facilitated diffusion，所以仍然属于Passive transport，而Na-K Pump则是属于Active transport。这样的划分能被接受吗？因为我实在找不出来还有什么protein function了... :(((

Pls correct me if I make any mistakes. My memory is already abit hazy cos I took this course in my first year.

Other than the sodium potassium pump, the presence of ion channels provides a way for the ions to diffuse through the membrane under the influence of both concentration forces and electrostatic forces. This diffusion helps to balance the membrane potential in the resting state. Ion channels are in fact protein molecules. This might be the thing that your lecturer talked about.

其实, 拿NA-K PUMP来做例子, 他是一个PROTEIN, 但是SERVE TWO FUNCTIONS, 一个是要ESTABLISH AND MENTAIN CHEMICAL POTENTIAL, ANOTHER IS FOR ELECTRICAL POTENTIAL.3 SODIUM IONS ARE PUMPPED OUT WHEN 2 POTASSIUM IONS ARE PUMPPED IN. SO BOTH CHEMICAL (NA OUTSIDE AND K INSIDE) AND ELECTRICAL (3-2) POTENTIAL ARE ALTERED. AND THERE ARE MANY OTHER PROTEINS, ION CHANNELS MAY FUNCTION AT THE SAME TIME FOR FINE TUNE OR SIGNALING. THEY MAY HELP IN ESTABLISHING ONE OR BOTH POTENTIALS. SO, IT IS NOT ABSOLUTE THAT ONE PROTEIN ONLY HAS ONE FUNCTION. AND IT IS SURE THAT MANY PROTEINS CONTRIBUTE TO ONE SAME FUNCTION.

but you used the term "diffuse" wrongly:). ions cannot diffuse through the membrane. "diffuse" means there are no facilitated channels needed and it means the substrate molecules cross the barrier spontaneously.

其实我在上那门课的时候，一大感觉就是整个一门课一直在吹牛，所有的东西只要吹个差不多就行了。真正理论上的东西老师要求的不是那么严格，感性认识就行。

还有啊watercooler，那种Protein Channel在Campbell的课本上也叫做Facilitated Diffusion，算是Passive Transport，当然有别于Simple Diffusion。谢谢你的答案，确实是用另一个角度来看这个问题。 :)))

but this faciliated diffusion does not function to the maintenance and establish this potential. or I should say, it does contribute to the equilibrium of the ion concentration on two sides, but the sensing proteins which really function for potentials are not them.

一种是和膜电位有关，包括各种形式的离子交换（主动或被动），另一种应该是物质运输，输送CNS发挥功能（一系列生理反应）所需的大分子。具体例子记不得了。