Deficiency of RITA results in multiple mitotic defects by affecting microtubule dynamics.

Area of Science:

• Cell Biology
• Molecular Biology
• Cancer Research

Background:

• Deregulation of microtubule (MT) dynamics is linked to chromosome instability in tumors.
• RBP-J interacting and tubulin-associated protein (RITA) is implicated in hepatocellular carcinoma.
• The molecular mechanisms of RITA's role in cancer are not fully understood.

Purpose of the Study:

• To investigate the molecular mechanisms of RITA's involvement in mitotic regulation and chromosome stability.
• To determine if RITA directly interacts with tubulin and affects microtubule dynamics.

Main Methods:

• In vitro and in vivo binding assays to assess RITA-tubulin interaction.
• Analysis of microtubule structure, stability, and dynamics in RITA-deficient cells.
• Assessment of mitotic progression and chromosome segregation.
• Re-expression studies with wild-type RITA and a tubulin-binding mutant (RITA Δtub).
• Investigation of RITA's interaction with histone deacetylase 6 (HDAC6).

Main Results:

• RITA binds to tubulin and localizes to mitotic MT structures, affecting MT structure.
• RITA deficiency leads to increased MT stability, reduced MT dynamics, and elevated acetylated α-tubulin.
• RITA-deficient cells exhibit chromosome misalignment and segregation errors.
• Re-expression of wild-type RITA, but not RITA Δtub, rescues these phenotypes.
• RITA interacts with HDAC6, and RITA suppression decreases HDAC6 binding to tubulin/MTs.

Conclusions:

• RITA is a novel regulator of MT dynamics, acting via tubulin interaction.
• RITA's deregulation contributes to chromosome instability through erroneous chromosome segregation.
• RITA's role in MT modulation is linked to HDAC6 activity.