Hhat is a palmitoylacyltransferase with specificity for N-palmitoylation of Sonic Hedgehog
Hhat is a palmitoylacyltransferase with specificity for N-palmitoylation of Sonic Hedgehog
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DOI：
10.1074/jbc.m803901200
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发表时间：
2008-08-08
影响因子：
4.8
通讯作者：
Resh, Marilyn D.
中科院分区：
文献类型：
--
作者：
Buglino, John A.;Resh, Marilyn D.
Sonic Hedgehog（Shh）的棕榈酰化对于有效的长距离和短距离信号传导至关重要。遗传筛选揭示了Shh，Hhat的潜在棕榈酰酰基转移酶（PAT），但Shh棕榈酰化的分子机制仍不清楚。在这里，我们已经开发并利用了一种体外Shh棕榈酰化测定来纯化Hhat至均一性。我们提供了直接的生物化学证据表明，Hhat是一种PAT，具有通过酰胺键连接棕榈酸酯至Shh的N-末端半胱氨酸的特异性。其他棕榈酰化蛋白（e. G. PSD 95和Wnt）不是Hhat的底物，并且豪猪（一种推定的Wnt PAT）不棕榈酰化Shh。Shh棕榈酰化既不需要自裂解也不需要胆固醇修饰。Shh前体和成熟蛋白都被Hhat N-棕榈酰化，并且反应发生在通过分泌途径的过程中。这项研究建立了Hhat作为一个真正的Shh PAT，并作为一个模型，了解分泌的形态发生蛋白是如何被不同的PAT修改。
Palmitoylation of Sonic Hedgehog (Shh) is critical for effective long- and short-range signaling. Genetic screens uncovered a potential palmitoylacyltransferase (PAT) for Shh, Hhat, but the molecular mechanism of Shh palmitoylation remains unclear. Here, we have developed and exploited an in vitro Shh palmitoylation assay to purify Hhat to homogeneity. We provide direct biochemical evidence that Hhat is a PAT with specificity for attaching palmitate via amide linkage to the N-terminal cysteine of Shh. Other palmitoylated proteins (e. g. PSD95 and Wnt) are not substrates for Hhat, and Porcupine, a putative Wnt PAT, does not palmitoylate Shh. Neither autocleavage nor cholesterol modification is required for Shh palmitoylation. Both the Shh precursor and mature protein are N-palmitoylated by Hhat, and the reaction occurs during passage through the secretory pathway. This study establishes Hhat as a bona fide Shh PAT and serves as a model for understanding how secreted morphogens are modified by distinct PATs.