Cell Division Mechanism (IMAGE) University of Pennsylvania School of Medicine Caption This is a montage of a fission yeast cell undergoing mitosis. The microtubule structures, including the spindle, are shown in red. The motor protein klp9p is shown in green. The motor binds to the spindle specifically at anaphase B onset, where it helps elongate the spindle. Credit Phong Tran, PhD, University of Pennsylvania School of Medicine; Developmental Cell Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.