Work

Human HTm4 is a hematopoietic cell cycle regulator

Year: 2002

Type: article

Abstract: Proper control of cell cycle progression is critical for the constant self-renewal, differentiation, and homeostasis of the hematopoietic system.Cells of all types share the common cell cycle regulators.The different expression patterns of common regulators, in a broad sense, define cell-type or lineage specificity.However, there remains the possibility of hematopoietic cell cycle regulators tailored to the demands of the hematopoietic system.Here we describe a novel protein, HTm4, which serves as a hematopoietic cell cycle regulator.Our data indicate that HTm4 is expressed in hematopoietic tissues and is tightly regulated during the differentiation of hematopoietic stem cells.It binds to cyclin-dependent kinase-associated (CDK-associated) phosphatase-CDK2 (KAP-CDK2) complexes, and the three proteins demonstrate similar patterns of cellular expression in human lymphoid tissues.HTm4 stimulates the phosphatase activity of KAP, and its C-terminal region is required for binding to KAP-CDK2 complexes and the modulation of KAP activity.Overexpression of HTm4 can cause cell cycle arrest at the G 0 /G 1 phase.Thus, HTm4 is a novel hematopoietic modulator for the G 1 -S cell cycle transition.

Source: Journal of Clinical Investigation

DOI: 10.1172/jci200214025