Can't call function from field of a struct in class

Question

I was in the middle of transferring my code for animation into a separate class when I encountered this error. The code was working fine before transferring into a class as I had to add a lot of manual changes to make it work inside of class

Basically I have a class UI, a struct for storing current animations with a pointer that calls a function for rendering every frame.

class UI
{
private:
  struct AnimSeq
  {                                               // A struct for intercepting every animation at the same time synced with 60hz timer
    void (UI::*renderFunc)(struct AnimSeq *self); // A function that executes every frame of animation. The whole AnimSeq object is considered empty if this pointer equals NULL.
    uint8_t step;                                 // Current frame of animation (gets updated with every frame)
    uint8_t duration;                             // Duration in 60 frames per second (interpolated, if FPS is set to less than that)
    int16_t offset[2];                            // Should be used to offset drawing current animation if whole object moves
  };

  struct AnimSeq *AnimQueue[4];
  
  void renderAnim_MenuCornerSlide(struct AnimSeq *self); // An example of rendering animation

void UI::HandleAnimation()
{
    if (!isEmpty())
    {
        for (uint8_t i = 0; i < 4; i++)
        {
            if (AnimQueue[i]->renderFunc != NULL)
            {
                AnimQueue[i]->renderFunc(AnimQueue[i]); // here's the error
            }
        }
    }
}

My compiler shows an error on the line above that I can't even understand because the message seems to have nothing to do with actual error: Expression Preceding Parentheses of Apparent Call Must Have (Pointer-To-) Function Type

I tried making AnimQueue not pointer type and encountered a whole lot of new errors. Also tried making all sorts of * and () on that particular line and nothing worked.

Can someone explain what happens here and how to fix it?