Probable E3 ubiquitin-protein ligase that functions downstream of HAL3 and is required for HAL3-regulated plant growth. Activation of HIP1 by HAL3 may lead to the degradation of cell cycle suppressors, resulting in enhancement of cell division and plant growth. S-ubiquitinyl-[E2 ubiquitin-conjugating enzyme]-L-cysteine + [acceptor protein]-L-lysine = [E2 ubiquitin-conjugating enzyme]-L-cysteine + N(6)-ubiquitinyl-[acceptor protein]-L-lysine. Protein modification; protein ubiquitination. Interacts with HAL3. By pantothenate. The RING-type zinc finger domain mediates binding to an E2 ubiquitin-conjugating enzyme. Belongs to the RING-type zinc finger family.